Thanks again Geoff. Last night I had a chance to peruse Hagadorn's book which has a photo' of AR633 with 510 Sqn, so that's a start. According to him somewhere between 25 and 49 P&W-powered Mohawks were taken over by the RAF, more than enough for second-line use I would have thought. I believe the RAF/FAA found use for somewhere around 25 ex-French Marylands, 8+ Belgian Buffalos and 10+ Greek Wildcats, so reverse throttles and metric instruments cannot have been too big a problem.
And thanks too Jim. Hagadorn's book has those shots also - another option for the model.