You are more likely to get a reply by mailing Steve Hillier directly. But you can register with the dubstar info service by sending your name and address to:
If you're writing from outside the UK then leave out the 'FREEPOST' and stick a stamp on the envelope.
But don't expect any miracles.. it's a terrible service, all I've had out of them are two postcards advertising the release of Stars and Elevator Song, and each arrived about a week after the singles had been released. I also got some info about a gig in Newcastle, but it arrived the day after the gig!
Anyway, try your luck, you never know what might happen if enough people write to them....