Address not being found when applying for credit files

Hi everyone , was wondering if anybody out there has come across my problem and so how to resolve it?
I am in my early fifties, been married and divorced, have kids, have had mortgages etc. etc.. I have recently bought a flat, which is a new conversion of an office block so now have another mortgage (my only one at the moment!). I have been employed for 34 years and earn a decent salary, am on the electoral role and my post code is registered with the Royal Mail, I have BT/Sky, have no ccj's and no money arrears..........................nothing too exciting so far !!!!................so how come none of the main credit checking sites, Experian etc. will accept me???. When a put my post code into their system only around four of the flats in my block (there is a total of 34 flats) comes up as an option and they wont accept me putting it in manually. I was with one of the credit rating sites before I moved to my new place but left because they charged a monthly fee.
Am concerned that I will not be eligible for credit cards/loans etc. if companies cannot find me when they use one of the credit reference companies.........any advice as to how to rectify this?

Kind Regards


Mike