Thanks Erich, appreciated! The one by Peter Strassner, European Volunteers, is one that I looking to buy at the moment. I have one Wiking book from J.J.F stored in Sweden, a good one, can't remember the author as I got 15 years ago or so, don't think that it's Strassner though.
Also found two in Italian by Alfero Massimiliano, and it seems to be one coming out in November too, Hitler's Vikings: Scandinavians in the Waffen-SS by Jonathan Trigg....