No worries Malone, I googled it, abbreviation of the Latin word Rex(King)..I learn something new every day:)..Thanks again for your help, I'd be lost without it:)
Glad I could help. R = king is because R stands for Rex, Latin for King. R = Queen too, as it can stand for Regina (Latin). You sometimes get ER - that's Elizabeth Regina (our present Queen) or it can mean Edwardus Rex, King Edward.
No worries, yidreg - I was checking it out in Chambers and making sure I had it all correct. It's just something I've seen used a lot, so I didn't give it much thought today.