Mum uses the AutoGlym fabric roof kit (cleaner+protector) on her old SL.... I have to say it works a treat....
However, the Superguard repels most things such as rain, bird plop and other lovely things that nature throws at us.....I have it on mine, and so far I have just had to hose of the top to get rid of the dust and bits.....
Have fun, Jon


P.S. Sorry... couldn't resist it!!