The success of the Achilles Class cruiser tank led to many derivatives, the foremost of which was the Amphion Class APC.
Utilising the same chassis and drivetrain as the Achilles made for a fast and reliable APC, allowing the Ironside infantry to accompany the cruiser tank formations into battle. It was soon discovered that the dual light machine gun armament was inadequate and many heavier weapons were retrofitted in the field.
Like the Achilles the Amphion was lacking in armour which made it unsuitable for frontal assaults. Still the design was successful in both the scouting and tactical manoeuvre role.
When Old Albion surrendered to the forces of Unity many Amphion tanks came to be used by the Tempest Legions where they would see service (with yet more retrofitted weaponry) until the end of the Unification campaign before being placed into reserve. A handful of examples would be pulled from reserve due to a dire shortage of more modern APCs during the civil war.
Update to my original Prototype APC, I have named it the Amphion class:
Fixed non-manifold parts. Modified a few details that didn't come out well when printed on the V1. Changed the track shape to make it easier to support/print. Added a new hatch gun option. Updated the Chimneys and Tow Hook to help with elephants foot - just stick them directly on the build plate. Added some detail to the bottom so it's less boring and to help it print better. Re-hollowed and re-supported.