Again, a clear, helpful, and informative post from somebody who knows what he is talking about. Thanks @nelly .
Possibly, although the stamp just records the date and mileage of a service, and I couldn't see anywhere in the book that it stated that the Ducati service schedule was followed if stamped but it may be an official thing I guess. I ended up saying to him, just write on the service book, "forks not serviced" which he ultimately agreed to. But it does present a problem for people like me, hence I use Louigi Moto who has no issue whatsoever in stamping the book.
Just to add insult to injury, 2 yrs ago I had my 1200s 15k service done in Málaga by the Ducati dealership. They only charged me around £300. Cam belt done and all the other oils & filters etc. Plugs checked but not changed and no valve checks (in my opinion, don't mess with it if it ain't broken! ). I just happened to be touring Spain when the service interval came round. Glad I went to ask if they could fit me in!
Taking the cam covers off and having a look at the valve clearances is not that difficult - and if they are within tolerances "don't mess with it if it ain't broken" is a fair approach. Refusing even to look at them, even after 15,000 miles, is sticking your head in the sand.