There should not be any fails like this due to credit if you are sure that you have no adverse credit history. Perhaps its worth going to experian or equifax and get your credit report?
As far as your residential house, you ought to convert it to a buy to let - just a quick phone call to your lender and request 'consent to let' and that makes it all above board.
Address detail shouldnt auto fail you anyway, and if you are going through a broker they will be able to find out why its failing anyway.
Anthony
http://www.comparethemortgagemarket.com