Hopefully not a bum steer, and I know aviation art, the guys most likely to have done such a painting are Frank Wootton or John Young. Both also have many paintings in the RAFM collection.
AL1. If it is a silver Canberra in a right hand bank with the harbour visible in the background, then the answer is John Young. You can find it on a 'flown envelope' having flown in a UK based T4.
VGC Autographed 30th Anniversary Commemorative First Day Cover "Canberra " 1983 | eBay