Agree.
Taff - there is help out there, albeit harder to find in some places than others I know. I think that part of the trouble may be that having been self reliant for so long you've either fallen out of the loop or simply never been in it and never made the contacts which could now be of great help in this situation. We didn't even know about DLA until a friend with a severely disabled daughter told us. Up until then we'd just got on with supporting our lad and any decent parents would do and were ignorant of so many things. If we'd been reliant on GP reports we too would have a problem because our lad never sees them but they are the key to other services for your son and indeed you because you need help too.
I'd have thought GP contact would be a very good thing too and possibly a referral to relevant health services. I know a few people who've obtained their own expert opinion to assist their cases, having been turned down for DLA or whatever. It costs money but not necessarily a large sum so that may be another route to consider given what's at stake for all of you. Now's the time to find and ask for help mate, including help for carers which is what you and your wife are.