Post ASD Diagnosis and Benefits Applications advice.

You might find the advice on these websites helpful - they cover each stage of the process in detail, including discussing suitable forms of evidence. They discuss, for example, providing evidence of how your conditions affect you, in respect of the various activities covered in the claim forms (PIP isn't awarded just based on having conditions that have been diagnosed):

Turn2us - Get Personal Independence Payment (PIP) documents) - covers examples of supporting evidence

Benefits and Work - Personal Independence Payment (PIP) (paid subscription required to access downloadable guides)

Citizens Advice - How to claim PIP

There'a also some advice here from the NAS, although it's pending an update:

NAS - Personal Independence Payment

You might like to consider using an advocacy service to help you. You might be able to find one here, for example:

NAS - Autism Services Directory

You might find the advice on these websites helpful - they cover each stage of the process in detail, including discussing suitable forms of evidence. They discuss, for example, providing evidence of how your conditions affect you, in respect of the various activities covered in the claim forms (PIP isn't awarded just based on having conditions that have been diagnosed):

Turn2us - Get Personal Independence Payment (PIP) documents) - covers examples of supporting evidence

Benefits and Work - Personal Independence Payment (PIP) (paid subscription required to access downloadable guides)

Citizens Advice - How to claim PIP

There'a also some advice here from the NAS, although it's pending an update:

NAS - Personal Independence Payment

You might like to consider using an advocacy service to help you. You might be able to find one here, for example:

NAS - Autism Services Directory