NHS right to Choose full provider list

Hi All, 

My GP has agreed to me having an Autism Assessment, I recognised I was probably on the spectrum in my 20's but until now I did not feel the need to be officially assessed, I'm now 54 and really starting to struggle. 

I am trying find a full list of adult autism assessment providers who I can choose for my assessment, does anyone know how to find a full list of providers and their waiting times online, 

Thanks in advance

Tim