Sorry, the two on the right are wearing flying suits. A suit is a two-piece garment. The growbag is a coverall. The winter two-piece is a flying suit.
These flying suits were issued to Mark 2 V-bomber crews and Lightning crews. The clue is to sewn down epaulettes. The later lookalike battle dress had proper epaulettes.
Sometime we would simply remove the jacket and pull a flying coverall over the top. We invariably flew with all our flying suits in a diversion bag so that we would be nattily dressed in case of diversion.
At Prestwich once, as our crew was correctly dressed but the bosses crew only had grow bags I was despatched to the airport terminal to buy diversion kit. For the bosses crew it was one of everything. Our crew settled for one razor with 5 blades, one tube of tooth paste and 5 toothbrushes. We had lots of spare drinking tickets.