Thank you very much everyone for your ideas! I actually added up the "definite Raphael"s and "definite Gabriel"s just as a matter of interest (the online equivalent of tossing a coin maybe) and it was 8 - 8 each. Argh!!
Anyway, given I do like Gabriel, I just have a problem with the nickname "Gabe" - so I said to DH if we can come up with a better nickname, we'll go with Gabriel Flynn.
Obviously when he's older we have a lot less control over who calls him what, but if he has an established nickname when he's younger maybe it'll make the difference. And besides, I don't have to call him "Gabe" unless he demands it of me and if that's the case I'll deal with it as it'll be his wish.
So what other nicknames are there/could we get away with? Somebody suggested Gabe pronounced "Gay-bee" which isn't too bad, but I wondered how realistically we could get away with say "Eli" (and if so, how would it be pronounced?) Would "El-lee" sound too feminine? Or indeed any other variants?