Hi, Andy... sorry for the abbreviation - PMC = Passau Museum Collection - there is a seven volume set of books (in German) called Das Böhmische Glas, which is a review of the Bohemian glass collection in the Passauer Glasmuseum that dates from 1700-1950. It's pretty expensive (about $350 USD), but even though I don't read German, it's been one of the best investments I've made. I recommend it to anyone who is going to seriously dive into collecting Bohemian glass.
At any rate - £80 for the whole lot is a great deal! Congratulations!
I looked back through my books, as I was trying to remember where I saw decoration similar to this, and it wasn't Riedel. My guess is that your pitcher may have been made by Poschinger. They did a lot of this enamel with the kind of matte finish. I'll see if I can find an example on line. Fortunately, the Poschinger glass works are still in operation, so it may be possible to contact them and simply ask. They have a website, and their email is firstname.lastname@example.org.