Hi Michael
I have moved your post to its own place. We asked people not to ask questions on someone else's post as it can lead to confusion. (The post you attached yours to was 7 years old)
When anyone makes a benefit claim, the DWP has a right to ask claimants to provide proof of income, savings and expenditure over a number of years. Five years is a long time - but you are not alone - one of our members was asked for proof of seven years recently.
Sorry not to give you better news.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems