The same applies with utility bills, keep these as these will be needed as evidence of address. Another way to cover this off is via the Voters Roll. All lenders will want to see an address history via the votes roll, so make sure you are on this, even if you never want to vote.
Finally set up that Direct Debit for those credit cards. Do Not get caught out with a late payment on your credit file, something as simple as a missed payments is likely to mean you are not able to secure a mortgage especially if you are looking at higher loan to values, were lenders are extremely cautious.