Camping cheques - Rhineland/Moselle regions?

We wanted an autumn break along the Rhine/Moselle but on checking the Camping Cheques map,  it seems that many sites in that region are not in the scheme anymore.  This then means that we cant take advantage of the excellent Club discounts on a ferry crossing from Hull - Zeebrugge (you have to buy a minimum of 7 cheques) - so if we buy the minimum we are unable to use them in the area of Germany/France we want to visit!!!  This is then an addition cost of almost £100 on the ferry crossing (which is already expensive)!! Anybody found this problem?