Hi jonnijon,
After a couple of days of trying their link for the form without any luck I phoned them and they said the website wasn't working so go to the office. They informed me about having a photo and copies of the ACR card and passport stuff.

Went to the office. Arrived around 12 noon. They had a desk outside with the form and plenty of tables for form filling. I asked the lady at the desk to mark the questions I needed to answer. Just my name, address, ACR number, passport number, DOB and the name and DOB of my wife.
That was it. Into the office hand over the docs, make payment P310, get copy of the receipt and hand over that was it. For me it was a maximum 15 mins only.
All done.

Even had time to get to the BIR office to try and get a TIN number and cert of residence. That was the nightmare visit.

Did you get this for your UK tax relief ?
How?