I havent had a chance to unfortunately. I plan to take a trip to GER mid year though on a rauchbier mission. Altbier doesnt seem to filter over here either which is unfortunate. The only kolsch on draft here is Fruh and Kuppers too, which are both pretty average.
I'm putting in an order from onlyfinebeer.co.uk soon though, which will include all the Kolsch and Altbier available.