Evan, codes at the time were 'XA', but I don't have an example of aircraft actually carrying the full codes. It might have been that only an individual aircraft letter was carried at this time. being Coastal Command, the camouflage scheme would more than likely be the Dark Sea Grey/Extra dark Sea Grey, with codes (if any) in Medium Sea Grey.
The Squadron was formed with Beauforts, but these were replaced by Blenheim IVs before the Squadron became operational, and in turn, after only just under three months, the Blenheims were replaced by Hampden Mk1 torpedo bombers, with which anti-submarine operations were commenced, over the Bay of Biscay, in May 1942.
From the info I have, which is brief, it would seem that the squadron was non-operational, being under training, conversion, or 'work-up', until Ops commenced in May '42, on Hampdens.