Can I replace the rubber seal on our Bosch Classixx6 1200 Express?

Yes they can be replaced at a reasonable cost...but they are tricky to do for a first-timer. A service tech would be able to do it in under 30mins. You'll need best part of a day & plenty of patience. The process is too long-winded to explain here but if you want to give it a go feel free. Basically the whole front of the machine needs to be removed to gain access.
Parts available from http://shop.ukwhitegoods.co.uk/Washing+Machine+Parts/Bosch/Bosch+Door+Seals.htm

Mike
October 2009