Bomber Command lost 55,000 aircrew during the war, and then bomber aircrew fought and died with Coastal Command, Air Forces Middle East, the Far East Air Force, etc.
You need your great uncle's full name (Uncle Frank may have been Sidney Francis Jones) and ideally his service number. Those would probably be engraved on his medals, and would be in any documentation that your Great Aunt might have had.
With his name and number, his service record is easy, and from that his stations and squadrons. With those you can look at the operational record books at Kew.
Without that, and without knowing where he was stationed, or what type of aircraft he flew, it's hard to know where to start.