Nearlyexraf, I would not have thought so, I was in the exact same situation just over 10 years ago i.e. about to leave the RAF and had a 2 year old drink drive conviction. It did not affect me. What is more likely to affect your chances is your trade, blanket stackers and shineys – not much hope. Most techie trades have a reasonable chance.
If i can give you some additional advice, do NOT waste your resettlement grant on one of these ROV courses. If you have a good trade behind you I would spend it on an offshore survival course and medical.
Reason being, whether you do an ROV course or not you will still be taken on as a trainee. A trainee with no survival or medical is an expense to the operating company.
I don’t know if you can still do a work placement as part of your resettlement, if so ring around a few of the operating companies and offer your services for free for 2/4 weeks(afterall the RAF are still paying your wages and expenses). I did 2 weeks with 2 different companies and both offered me work. The resettlement centre in Aberdeen (If it still exhists) will be able to help withcontact names etc.
Finally if you have a RAF c*ck tash, get rid.
Good luck.