If its a flat, particularly if its a house thats been subdivided in the past, check that the address you're giving matches the address as its stated on the electoral roll / council tax bill.
I've had credit check bother in the past and its always been down to there being an ambiguity as to how the address can be stated, for instance:
"Flat 3" versus "Flat 03" versus "Flat 0/3"
or
"Top Left" Versus "Flat 3/2".
For me it didn't matter whether all the existing accounts, credit agreements, utilities etc were using on version of the address, it was the one that the electoral roll used that mattered, because if that didn't match its as if you're not on the roll.
I had to get in touch with experian and get them to merge / disabiguityalize* the address versions and agree a specific expression of the address to use with future apps.
Annoyingly the last 6 address I've had 5 had variable ways of giving the address, so when some credit checks need you to go back several years its a mine field!
* yes really