diff --git a/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-cran.mustache.yaml b/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-cran.mustache.yaml
index 6c67f7d4dd..d2fcaf83f3 100644
--- a/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-cran.mustache.yaml
+++ b/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-cran.mustache.yaml
@@ -1,19 +1,19 @@
 #cloud-config
 
-# We know that exactly one data disk will be attached to this VM and we currently start numbering from lun1
+# We know that exactly one data disk will be attached to this VM and we currently start numbering from lun0
 disk_setup:
-  /dev/disk/azure/scsi1/lun1:
+  /dev/disk/azure/scsi1/lun0:
     table_type: gpt
     layout: true
     overwrite: true
 
 fs_setup:
-  - device: /dev/disk/azure/scsi1/lun1
+  - device: /dev/disk/azure/scsi1/lun0
     partition: auto
     filesystem: ext4
 
 mounts:
-  - [/dev/disk/azure/scsi1/lun1-part1, /datadrive, ext4, "defaults,nofail"]
+  - [/dev/disk/azure/scsi1/lun0-part1, /datadrive, ext4, "defaults,nofail"]
 
 # Configure apt repositories
 apt:
diff --git a/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-pypi.mustache.yaml b/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-pypi.mustache.yaml
index 3507b51dbd..fe4359b297 100644
--- a/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-pypi.mustache.yaml
+++ b/deployment/safe_haven_management_environment/cloud_init/cloud-init-repository-mirror-internal-pypi.mustache.yaml
@@ -1,19 +1,19 @@
 #cloud-config
 
-# We know that exactly one data disk will be attached to this VM and we currently start numbering from lun1
+# We know that exactly one data disk will be attached to this VM and we currently start numbering from lun0
 disk_setup:
-  /dev/disk/azure/scsi1/lun1:
+  /dev/disk/azure/scsi1/lun0:
     table_type: gpt
     layout: true
     overwrite: true
 
 fs_setup:
-  - device: /dev/disk/azure/scsi1/lun1
+  - device: /dev/disk/azure/scsi1/lun0
     partition: auto
     filesystem: ext4
 
 mounts:
-  - [/dev/disk/azure/scsi1/lun1-part1, /datadrive, ext4, "defaults,nofail"]
+  - [/dev/disk/azure/scsi1/lun0-part1, /datadrive, ext4, "defaults,nofail"]
 
 # Configure apt repositories
 apt:
diff --git a/deployment/secure_research_environment/cloud_init/cloud-init-codimd.mustache.yaml b/deployment/secure_research_environment/cloud_init/cloud-init-codimd.mustache.yaml
index 890c39d5e3..45e9bb72b7 100644
--- a/deployment/secure_research_environment/cloud_init/cloud-init-codimd.mustache.yaml
+++ b/deployment/secure_research_environment/cloud_init/cloud-init-codimd.mustache.yaml
@@ -124,18 +124,18 @@ packages:
 package_update: true
 package_upgrade: true
 
-# We know that exactly one data disk will be attached to this VM and it will be attached as lun1
+# We know that exactly one data disk will be attached to this VM and it will be attached as lun0
 disk_setup:
-  /dev/disk/azure/scsi1/lun1:
+  /dev/disk/azure/scsi1/lun0:
     table_type: gpt
     layout: true
     overwrite: true
 fs_setup:
-  - device: /dev/disk/azure/scsi1/lun1
+  - device: /dev/disk/azure/scsi1/lun0
     partition: auto
     filesystem: ext4
 mounts:
-  - [/dev/disk/azure/scsi1/lun1-part1, /data, ext4, "defaults,nofail"]
+  - [/dev/disk/azure/scsi1/lun0-part1, /data, ext4, "defaults,nofail"]
 
 # Set hostname
 fqdn: {{sre.webapps.codimd.fqdn}}
diff --git a/deployment/secure_research_environment/cloud_init/cloud-init-gitlab.mustache.yaml b/deployment/secure_research_environment/cloud_init/cloud-init-gitlab.mustache.yaml
index b887420e2b..845fa9ad7a 100644
--- a/deployment/secure_research_environment/cloud_init/cloud-init-gitlab.mustache.yaml
+++ b/deployment/secure_research_environment/cloud_init/cloud-init-gitlab.mustache.yaml
@@ -114,18 +114,18 @@ packages:
 package_update: true
 package_upgrade: true
 
-# We know that exactly one data disk will be attached to this VM and it will be attached as lun1
+# We know that exactly one data disk will be attached to this VM and it will be attached as lun0
 disk_setup:
-  /dev/disk/azure/scsi1/lun1:
+  /dev/disk/azure/scsi1/lun0:
     table_type: gpt
     layout: true
     overwrite: true
 fs_setup:
-  - device: /dev/disk/azure/scsi1/lun1
+  - device: /dev/disk/azure/scsi1/lun0
     partition: auto
     filesystem: ext4
 mounts:
-  - [/dev/disk/azure/scsi1/lun1-part1, /data, ext4, "defaults,nofail"]
+  - [/dev/disk/azure/scsi1/lun0-part1, /data, ext4, "defaults,nofail"]
 
 # Set hostname
 fqdn: {{sre.webapps.gitlab.fqdn}}
diff --git a/deployment/secure_research_environment/cloud_init/cloud-init-postgres.mustache.yaml b/deployment/secure_research_environment/cloud_init/cloud-init-postgres.mustache.yaml
index 2a6c8f707b..997ea60e68 100644
--- a/deployment/secure_research_environment/cloud_init/cloud-init-postgres.mustache.yaml
+++ b/deployment/secure_research_environment/cloud_init/cloud-init-postgres.mustache.yaml
@@ -16,20 +16,20 @@ apt:
       source: "deb http://apt.postgresql.org/pub/repos/apt/ focal-pgdg main"
       keyid: 7FCC7D46ACCC4CF8
 
-# We know that exactly one data disk will be attached to this VM and it will therefore use lun1 as lun0 is the OS disk
+# We know that exactly one data disk will be attached to this VM and it will therefore use lun0
 disk_setup:
-  /dev/disk/azure/scsi1/lun1:
+  /dev/disk/azure/scsi1/lun0:
     table_type: gpt
     layout: true
     overwrite: true
 
 fs_setup:
-  - device: /dev/disk/azure/scsi1/lun1
+  - device: /dev/disk/azure/scsi1/lun0
     partition: auto
     filesystem: ext4
 
 mounts:
-  - [/dev/disk/azure/scsi1/lun1-part1, /data, ext4, "defaults,nofail"]
+  - [/dev/disk/azure/scsi1/lun0-part1, /data, ext4, "defaults,nofail"]
 
 write_files:
   - path: "/etc/apt/apt.conf.d/00proxy"
diff --git a/deployment/secure_research_environment/cloud_init/cloud-init-srd.mustache.yaml b/deployment/secure_research_environment/cloud_init/cloud-init-srd.mustache.yaml
index 45fa5f7ec9..2f71773134 100644
--- a/deployment/secure_research_environment/cloud_init/cloud-init-srd.mustache.yaml
+++ b/deployment/secure_research_environment/cloud_init/cloud-init-srd.mustache.yaml
@@ -4,19 +4,19 @@
 package_upgrade: false
 
 disk_setup:
-  /dev/disk/azure/scsi1/lun1:
+  /dev/disk/azure/scsi1/lun0:
     table_type: gpt
     layout: true
     overwrite: true
 
 fs_setup:
-  - device: /dev/disk/azure/scsi1/lun1
+  - device: /dev/disk/azure/scsi1/lun0
     filesystem: ext4
     partition: auto
 
 # Note that we do not include the blobfuse mounts here as these are controlled by systemd
 mounts:
-  - ["/dev/disk/azure/scsi1/lun1-part1", /scratch, ext4, "rw,user,exec"]
+  - ["/dev/disk/azure/scsi1/lun0-part1", /scratch, ext4, "rw,user,exec"]
   - ["{{sre.storage.userdata.account.name}}.file.core.windows.net:/{{sre.storage.userdata.account.name}}/shared", /shared, nfs, "_netdev,sec=sys"]
   - ["{{sre.storage.userdata.account.name}}.file.core.windows.net:/{{sre.storage.userdata.account.name}}/home", /home, nfs, "_netdev,sec=sys"]