Hi Victoria
I've skimmed that post but I'll read it again... I have a huge stack of things that I've saved as evidence...among them are
All our joint checking account statements, Pete's single account statements, both of our wages slips and tax forms like P-60s etc, for me I have letters from Customs, letters addressed to both of us from the local council after we applied for council housing, some bank letters addressed to both of us, Pete's credit card statements, letters addressed to Pete from his work's union, a letter from a dog charity addressed to Pete and a Slimming World letter addressed to me. I also have travel insurance documents that show both our names were insured from our holiday and a hotel booking for both of us for our holiday. Oh and letter that had my NI number, medical card, and DVLA letters for my two driving tests, theory test etc.
I may have a few other bits but I'll have to organize it soon to really see what I have.