Procedure for self referral

I live in Essex and have found a place where you can refer yourself for a diagnosis for autism and aspergers. What are anyone else's experiences of self referral? what was the procedure and how long did it take? Where there any costs involved? Im 51 and have just been inspired to try this having watched the Chris Packham documentary. I have been unemployed for about 25 years and now the only job I have found is dishwashing although I have got a degree and am musical and artistic .