Accessing NHS Medical Records

I have asked my GP surgery to give me access to my NHS medical records back to childhood. This is an attempt to find something from them which will prove to be the 'hard' documentary evidence of early autism that my autism assessor is demanding from me.

Despite the obstructive attitude of the GP's Receptionist I managed to fill in a form at the GP surgery, and was told it would be sent on to their main branch for processing. I won't be able to follow it up until tomorrow so I am still waiting....

My questions are:

How long does this usually take in reality (ie: to actually get to see the records)?

Will I need some sort of reference book to decode the medical jargon in the records, and if so what can I use? Or is it written in plain English?

What kind of thing will I be looking for with relevance to autism?

Do NHS autism assessors already look at your full health records? My assessor previously told me she'd seen my care records, but during out first assessment meeting I could tell she didn't know all about my medical conditions at all, (or did she?)

Would be grateful for any insight of previous experience with this, especially with regard to what is relevant to signs of autism.

Thanks.