"...I think you're legally obligated to keep all paperwork for at least 3 years. I still have bank statements from the '80s up in the loft." Presumably this is

"...I think you're legally obligated to keep all paperwork for at least 3 years. I still have bank statements from the '80s up in the loft." Presumably this is for tax purposes, in case they're audited? If that's the case, your friends are out of date - HMRC (the tax authority) has accepted scanned documents in place of originals for some time now.