Hi Coldicote,
Last week, I spent the best part of six hours, trying to organise paperwork and put things away in the new cupboards my partner has constructed. After 6 hours, the living room still looks like a tip, I have at least 5 black bin liners full of shredded paper, envelopes and packaging.
As for the bank statements, after spending half an hour trying to file them, I had enough and anything from 2 years ago or more, have just been shredded. I don't know the policy of any banks, but I have been able to order duplicate statements from my bank, 2 years back. (I have also disposed of bills from a year ago or more)
I suppose if you are concerned, then an idea might be to scan documents, you feel are important, then keep them on your computer, in the unlikely event you will need them again. With bank statements, why not request electronic ones via online banking, then they can be stored in folders on your PC.