PPI Claim Bank Addresses Needed Please

As the title suggests I am trying to find the correct/appropriate addresses of the following banks to send in my PPI reclaim forms to

Northern Rock
Abbey
Bank of Ireland
Coventry
Natwest
Santander
Alliance & Leicester

I have tried searching the net but there doesn't appear to be a definitive address for each?

Do I need to mark something on the envelope address like 'PPI Claims'?

Any help would be greatly appreciated

Michael