Appropriate evidence will depend on the type of your disability:

For health and impairments: a signed and dated letter or report from your GP or another suitably qualified professional confirming the nature of the disability, its impact on your studying and that it is a long-term condition.

For specific learning difficulties such as dyslexia and/or dyspraxia: a signed and dated full diagnostic report written by an Educational Psychologist or PATOSS approved Specialist Teacher.