The allgau region around Immenstadt, Sonthofen, and Obersdorf rival parts the Tyrol for ski runs and facilities. However my knowledge is a bit dated. been around 20 years since I last skied in that area.
I'm surprised Brit tour companies haven't developed business in Bavaria.
some ex army colleagues of mine went there to do a military ski package and i know they had a blast like and lots of snow this was back in 01 if my memory serves me right
Many years ago skied at Garmisch, Zugspitz and Oberjoch. Loved Bavaria, skiing was good, not many crowds and the atmosphere of the traditional villages was great and you can't beat german beer!!! If you can, try and spend a bit of time looking around Munich, worth a look.