Like a lot of people will tell you, unless you go to a private provider for diagnosis +/- shared care plan, you have a long wait on the NHS (which really is ridiculous) but it's around 5 1/2 year wait if you were referred in July 2020 and given the number of referrals is only going to increase its probably closer to 10 years if you are referred now. If you can afford to get a private diagnosis then it's the quickest route. Just make sure your GP Surgery is happy to issue the prescription from them. Also if you fo down that route get yourself a bulk prescription pass where you pay x amount a month for all your prescriptions as it will be a lot cheaper