We use a great cleaner for the tubes, Sea Power, they clean the tubes at the same time you get a new look of the tubes, it`s really great stuff, i tried the revival but i definetly prefer this one.
I don`t know were to by it in uk but the distributor in uk for this dutch brand is:
United Kingdom:
Contender UK Hampshire
Tel: +44-(0)1489 581715
Fax: +44-(0)1489 885117
general@contender.co.uk
Try it.
Regards
Petrov