I'm not sure if it's applicable but when we're registering for the wedding in the registry office and I was asked for a proof of address, I just showed the "spam" mail I got from Matalan showing my name and address here in UK and they said it's acceptable..
That's an absolute disgrace - is it any wonder there are so many sham marriages taking place ? Do us all a favour report your Registry Offices lax procedures to your local Police, The UKBA and Home Secretary (mayt@parliament.uk)