In addition to what HD said in post 27:
At the beginning of the NATS ATCO Cadet course you got a full PPL course. After this annually for 3 years you got 5 hours refresher flying at an allocated flying school. At the end of the cadet course ie after the third year, we got route flying in a twin of some sort (usually Apache/Aztec/ Seneca) where we just did radio navigation and RTF calls, the instructor doing the flying under our 'guidance'. This was followed by the 2 week course at BA where we flew basic sims (system trainers?) and learnt how the autopilot systems operated (pre FMS). My course was on the BEA Trident sims at Viking House, Southall.