Thank you all for your quick responses.
I'll keep asking questions and I'll let you know how I get on.
I would find it a bit strange if they would allow people who lost there sight during service to continue to serve and not allow someone with limited sight to join. I've had a lot more time to adjust to my vision and can now do pretty much anything that a normal sighted person can (except those magic eye pictures!).
Thanks again. It's nice to come to a forum with a good community spirit.