You must inform the DVLA if you have a diagnosis of ASD. Discuss with your doctor. You can be fined and prosecuted if you have not informed the DVLA.
Try and get the theory test done first as this will help with your understanding of the rules of the road. While doing this read Driving The Essential Skills. This will help with your understanding.
You should inform your instructor and discuss your needs with them. If you have additional sensory differences like problems with glare make sure they are aware. The more information your instructor has the better they will be able to help you.
As a pupil with autism expect that it will take you longer than others. Be aware that driving involves routines. But these can change very quickly according to the circumstances.
As an instructor do not expect any eye contact or very little. As always it is what you do normally but more so. Lots of stop starts, so there is lots of little breaks. Break the information down into small parts. Expect problems with sequencing at the start. Lots of practice will help these become embedded. There could also be a problem with judging space.
If your condition requires more attention. In our local area, Wessex Driveability over in Southampton offer a very professional and thorough assessment. The driving assessment will be conducted by a driving instructor with an occupational therapist sat in the back. They can be reached on 02380 554 100.
When seeking a suitable driving instructor Wessex Driveability maintain a register of suitable instructors that cover this area. You could also try Disability Driving Instructors on 0844 800 7355 who will have a nationwide register of specialist instructors.