We got ours from here http://www.wooden-blinds-direct.co.uk/
Also have cats and no damage to the blinds after 3 years.
Pleased with the quality and the delivery.

Cheers
Do you leave yours up off the windowsill a little so they can scoot under?
The above or http://www.blinds-2go.co.uk/ - I used blinds2go and they were great; their customer service were great for asking questions on stuff, could probably ask about the cat issue.