Taphappy
As you say, after June 1943, aircrew were no longer promoted to LAC at the end of ITW. A new system was introduced whereby AC2 was split into AC2 (Grade A), AC2 (Grade B) and AC2 (Grade C).
Those on the PNB Scheme (Pilots, Navigators and Bomb Aimers) were promoted from Grade A to Grade C on completion of ITW training, with 7/3d pay. All other trades would be promoted to Grade B, with 5/- pay.
[Source: C G Jefford, Observers and Navigators]
Looking forward to the next instalment.
Regards
Pete