diff --git a/.cirrus.yml b/.cirrus.yml
index 13105b13cc..bcf1c5cc25 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -87,7 +87,7 @@ linux_task_template: &LINUX_TASK_TEMPLATE
 # YAML alias for compute credits.
 #
 compute_credits_template: &CREDITS_TEMPLATE
-  # Only use credits for non-DRAFT pull-requests to SciTools/iris master branch by collaborators
+  # Only use credits for non-DRAFT pull-requests to a SciTools/iris branch by collaborators
   use_compute_credits: ${CIRRUS_REPO_FULL_NAME} == "SciTools/iris" && ${CIRRUS_USER_COLLABORATOR} == "true" && ${CIRRUS_PR_DRAFT} == "false" && ${CIRRUS_PR} != ""
 
 
diff --git a/lib/iris/fileformats/netcdf.py b/lib/iris/fileformats/netcdf.py
index bb7a870d58..2032f2349f 100644
--- a/lib/iris/fileformats/netcdf.py
+++ b/lib/iris/fileformats/netcdf.py
@@ -1043,7 +1043,7 @@ def write(
             dtype(i.e. 'i2', 'short', 'u4') or a dict of packing parameters as
             described below. This provides support for netCDF data packing as
             described in
-            http://www.unidata.ucar.edu/software/netcdf/docs/BestPractices.html#bp_Packed-Data-Values
+            https://www.unidata.ucar.edu/software/netcdf/documentation/NUG/best_practices.html#bp_Packed-Data-Values
             If this argument is a type (or type string), appropriate values of
             scale_factor and add_offset will be automatically calculated based
             on `cube.data` and possible masking. For more control, pass a dict
@@ -2589,7 +2589,7 @@ def save(
         (i.e. 'i2', 'short', 'u4') or a dict of packing parameters as described
         below or an iterable of such types, strings, or dicts.
         This provides support for netCDF data packing as described in
-        http://www.unidata.ucar.edu/software/netcdf/docs/BestPractices.html#bp_Packed-Data-Values
+        https://www.unidata.ucar.edu/software/netcdf/documentation/NUG/best_practices.html#bp_Packed-Data-Values
         If this argument is a type (or type string), appropriate values of
         scale_factor and add_offset will be automatically calculated based
         on `cube.data` and possible masking. For more control, pass a dict with
diff --git a/requirements/ci/nox.lock/Dockerfile b/requirements/ci/nox.lock/Dockerfile
deleted file mode 100644
index a989859356..0000000000
--- a/requirements/ci/nox.lock/Dockerfile
+++ /dev/null
@@ -1,36 +0,0 @@
-FROM condaforge/mambaforge:latest
-
-LABEL author="scitools" \
-      version="0.1" \
-      description="SciTools Cirrus-CI mambaforge image"
-
-# python version in "<major><minor>" format e.g., "38"
-ARG PY_VER
-
-ENV WORK_DIR="/root/scitools" \
-    LOCK_FILE="/root/scitools/iris.lock" \
-    NOX_DIR="/root/scitools/.nox" \
-    ENV_DIR="/root/scitools/.nox/tests" \
-    TMP_DIR="/root/scitools/.nox/tests/tmp"
-
-# configure conda and install conda-lock et al
-RUN conda config --set always_yes yes \
-  && conda config --set changeps1 no \
-  && conda config --set show_channel_urls True \
-  && conda config --add channels conda-forge \
-  && conda update --quiet --name base conda \
-  && mamba install --yes --quiet --channel conda-forge --name base conda-lock nox pip setuptools wheel
-
-# populate work directory with lock file from docker context
-WORKDIR ${WORK_DIR}
-COPY ./py${PY_VER}-linux-64.lock ${LOCK_FILE}
-
-# install the lock packages into the nox workspace and
-# configure the required nox environments
-RUN mkdir -p ${ENV_DIR} \
-  && mamba install --quiet --prefix ${ENV_DIR} --file ${LOCK_FILE} \
-  && ln -s ${ENV_DIR} ${NOX_DIR}/gallery \
-  && ln -s ${ENV_DIR} ${NOX_DIR}/doctest \
-  && ln -s ${ENV_DIR} ${NOX_DIR}/linkcheck \
-  && mkdir -p ${TMP_DIR} \
-  && sha256sum ${LOCK_FILE} | cut -d' ' -f1 > ${TMP_DIR}/py${PY_VER}.yml