Just as a point of discussion
I left the military several years ago and, at that time, the vast majority of mil aircraft (maybe all - but I can't 100% sure ) were Cat 1 only. Even the 550m viz limit was raised to 600m for all types.
When the RAF got their first Tristars from BA, the aircraft were Cat 3 capable but I believe the RAF did not train the pilots or maintain the aircraft to keep Cat 3 certification.
I am not sure of the current situation regarding the RAF and Cat 3.