diff --git a/__tests__/spec/data-storage.js b/__tests__/spec/data-storage.js
new file mode 100644
index 0000000000..e140e385f2
--- /dev/null
+++ b/__tests__/spec/data-storage.js
@@ -0,0 +1,76 @@
+/* eslint-env jest */
+const request = require('supertest')
+const app = require('../../server.js')
+const path = require('path')
+const fs = require('fs')
+const utils = require('../../lib/utils.js')
+
+jest.setTimeout(30000)
+
+function readFile (pathFromRoot) {
+  return fs.readFileSync(path.join(__dirname, '../../' + pathFromRoot), 'utf8')
+}
+/**
+ *
+ */
+describe('The data storage', () => {
+  // check session-data defaults file exists
+
+  it.skip('file should exist', (done) => {
+    const sessionDataDefaultsFile = readFile('app/data/session-data-defaults.js')
+
+    request(app)
+      .get(sessionDataDefaultsFile)
+      .expect('Content-Type', /application\/javascript; charset=UTF-8/)
+      // .expect(200)
+      .end(function (err, res) {
+        if (err) {
+          done(err)
+        } else {
+          done()
+        }
+      })
+  })
+
+  describe('storeData function', () => {
+    it('should add input data into session data', async () => {
+      let initialSessionData = {
+        'driver-name': 'Dr Emmett Brown'
+      }
+
+      const inputData = {
+        'vehicle-registration': 'OUTATIME'
+      }
+
+      utils.storeData(inputData, initialSessionData)
+
+      expect(initialSessionData).toEqual({
+        'driver-name': 'Dr Emmett Brown',
+        'vehicle-registration': 'OUTATIME'
+      })
+    })
+
+    it('should merge object into object', async () => {
+      let initialSessionData = {
+        vehicle: {
+          'driver-name': 'Dr Emmett Brown'
+        }
+      }
+
+      const inputData = {
+        vehicle: {
+          registration: 'OUTATIME'
+        }
+      }
+
+      utils.storeData(inputData, initialSessionData)
+
+      expect(initialSessionData).toEqual({
+        vehicle: {
+          'driver-name': 'Dr Emmett Brown',
+          registration: 'OUTATIME'
+        }
+      })
+    })
+  })
+})
diff --git a/app/data/session-data-defaults.js b/app/data/session-data-defaults.js
index 9e4921b0ab..3b5158abb9 100644
--- a/app/data/session-data-defaults.js
+++ b/app/data/session-data-defaults.js
@@ -16,9 +16,47 @@ Example usage:
 ============================================================================
 
 */
-
 module.exports = {
-
-  // Insert values here
-
+  // Example as used in current docs
+  claimant: {
+    field1: 'Example 1',
+    field2: 'Example 2',
+    field3: 'Example 3'
+  },
+  partner: {
+    field1: 'Example 1',
+    field2: 'Example 2',
+    field3: 'Example 3'
+  },
+  myObject: {
+    // Array of objects within object
+    myArrayOfObjects: [
+      {
+        name: 'test1',
+        address: 'test2'
+      },
+      {
+        name: 'test3'
+      }
+    ],
+    // Simple array within object
+    mySimpleArray: [
+      'test4',
+      'test5'
+    ],
+    // Multi-level array within object
+    myMultiLevelArray: [
+      [
+        ['test6', 'test7'],
+        'test8'
+      ]
+    ]
+  },
+  // Arrays within array
+  myArray: [
+    [
+      'test9',
+      ['test10', 'test11']
+    ]
+  ]
 }
diff --git a/docs/views/examples/pass-data/test1.html b/docs/views/examples/pass-data/test1.html
new file mode 100644
index 0000000000..ac507c3399
--- /dev/null
+++ b/docs/views/examples/pass-data/test1.html
@@ -0,0 +1,47 @@
+{% extends "layout.html" %}
+
+{% block pageTitle %}
+  Example - Passing data
+{% endblock %}
+
+{% block beforeContent %}
+  {% include "includes/breadcrumb_examples.html" %}
+{% endblock %}
+
+{% block content %}
+
+  <div class="govuk-grid-row">
+    <div class="govuk-grid-column-two-thirds">
+
+      <form action="/docs/examples/pass-data/test2" method="post" class="form">
+
+        <div class="govuk-form-group">
+          <h3 class="govuk-label-wrapper">
+            Example as used in current docs
+          </h3>
+          <input class="govuk-input" id="registration-number" name="[claimant][field1]" value="{{ data['claimant']['field1'] }}" type="text">
+          <h3 class="govuk-label-wrapper">
+            Array of objects within object
+          </h3>
+          <input class="govuk-input" id="registration-number" name="[myObject][myArrayOfObjects][0][name]" value="{{ data['myObject']['myArrayOfObjects'][0]['name'] }}" type="text">
+          <h3 class="govuk-label-wrapper">
+            Simple array within object
+          </h3>
+          <input class="govuk-input" id="registration-number" name="[myObject][mySimpleArray][0]" value="{{ data['myObject']['mySimpleArray'][0] }}" type="text">
+          <h3 class="govuk-label-wrapper">
+            Multi-level array within object
+          </h3>
+          <input class="govuk-input" id="registration-number" name="[myObject][myMultiLevelArray][0][0][0]" value="{{ data['myObject']['myMultiLevelArray'][0][0][0] }}" type="text">
+          <h3 class="govuk-label-wrapper">
+            Arrays within array
+          </h3>
+          <input class="govuk-input" id="registration-number" name="[myArray][0][0]" value="{{ data['myArray'][0][0] }}" type="text">
+        </div>
+
+        <button class="govuk-button">Continue</button>
+
+      </form>
+
+    </div>
+  </div>
+{% endblock %}
diff --git a/docs/views/examples/pass-data/test2.html b/docs/views/examples/pass-data/test2.html
new file mode 100644
index 0000000000..55b407b153
--- /dev/null
+++ b/docs/views/examples/pass-data/test2.html
@@ -0,0 +1,42 @@
+{% extends "layout.html" %}
+
+{% block pageTitle %}
+Check your answers
+{% endblock %}
+
+{% block content %}
+
+  <div class="govuk-grid-row">
+    <div class="govuk-grid-column-two-thirds">
+
+      <h3>Example as used in current docs</h3>
+      {{ data['claimant']['field1'] }}
+      {{ data['claimant']['field2'] }}
+      <br>
+      <br>
+      <h3>Array of objects within object</h3>
+      {{ data['myObject']['myArrayOfObjects'][0]['name'] }}
+      {{ data['myObject']['myArrayOfObjects'][0]['address'] }}
+      {{ data['myObject']['myArrayOfObjects'][1]['name'] }}
+      <br>
+      <br>
+      <h3>Simple array within object</h3>
+      {{ data['myObject']['mySimpleArray'][0] }}
+      {{ data['myObject']['mySimpleArray'][1] }}
+      <br>
+      <br>
+      <h3>Multi-level array within object</h3>
+      {{ data['myObject']['myMultiLevelArray'][0][0][0] }}
+      {{ data['myObject']['myMultiLevelArray'][0][0][1] }}
+      {{ data['myObject']['myMultiLevelArray'][0][1] }}
+      <br>
+      <br>
+      <h3>Arrays within array</h3>
+      {{ data['myArray'][0][0] }}
+      {{ data['myArray'][0][1][0] }}
+      {{ data['myArray'][0][1][1] }}
+    </div>
+
+  </div>
+
+{% endblock %}
diff --git a/lib/utils.js b/lib/utils.js
index b3adf58100..ac76bd25a0 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -220,7 +220,10 @@ exports.matchMdRoutes = function (req, res) {
 }
 
 // Store data from POST body or GET query in session
-var storeData = function (input, data) {
+function storeData (input, data) {
+  // Value we store to indicate unchecked checkboxes. See `auto-store-data.js`
+  var uncheckedValue = '_unchecked'
+
   for (var i in input) {
     // any input where the name starts with _ is ignored
     if (i.indexOf('_') === 0) {
@@ -230,32 +233,32 @@ var storeData = function (input, data) {
     var val = input[i]
 
     // Delete values when users unselect checkboxes
-    if (val === '_unchecked' || val === ['_unchecked']) {
+    if (val === uncheckedValue || val === [uncheckedValue]) {
       delete data[i]
       continue
     }
 
-    // Remove _unchecked from arrays of checkboxes
-    if (Array.isArray(val)) {
-      var index = val.indexOf('_unchecked')
-      if (index !== -1) {
-        val.splice(index, 1)
-      }
-    } else if (typeof val === 'object') {
-      // Store nested objects that aren't arrays
-      if (typeof data[i] !== 'object') {
-        data[i] = {}
-      }
+    if (typeof val === 'object') {
+      // If array contains `uncheckedValue`, it's array of checkboxes
+      if (Array.isArray(val) && val.indexOf(uncheckedValue) !== -1) {
+        // Remove `uncheckedValue` from arrays of checkboxes
+        val.splice(val.indexOf(uncheckedValue), 1)
+      } else { // Store arrays that don't contain "_unchecked", and nested objects
+        if (typeof data[i] !== 'object') {
+          data[i] = {}
+        }
 
-      // Add nested values
-      storeData(val, data[i])
-      continue
+        // Add nested values
+        storeData(val, data[i])
+        continue
+      }
     }
-
     data[i] = val
   }
 }
 
+exports.storeData = storeData
+
 // Get session default data from file
 let sessionDataDefaults = {}