It seems the documents you need to apply for an APRC vary depending on your individual circumstances.
When you go to the NIA to apply for one, do they expect you to have gathered the documents you need, or will they take your application form and then give you a checklist of documents you need to collect?
I rang them and they told me the list of papers needed over the phone.
They will not take your application until you have all the required documents. You can call your local office before heading there to get the checklist. The usual suspects are:
If you are doing it from a marriage ARC, then I don’t know if you need something else.