I've just ordered a new cover from here http://www.seaswan.co.uk/
It won't be with me for a few days so I can't comment on the product, but the service so far from Mark at Seaswan has been excellent. I completed the measurement form online and sent it through one evening. The next morning I had a quote from him to make the cover in different weights of material. We exchanged a few emails, including a picture or two of the boat, and his replies were always very prompt and helpful.