Hi Tim,
I am from Hamburg and own a house near Saas Fee and know the area very well.
I don´t think it is possible to go Snowkiting. I don´t know if you ever been to Saas Fee, but there you will find the following situation: Saas Fee is up on a hill with very huge mountains around (e.g. the "DOM", the highest mountain totaly on swiss ground), so you won´t find much flat area in Saas Fee. Only at the end of the village there is a flat area, but some ski-lifts around, not so good.
The other villages under Saas Fee, e.g. "Saas Grund" (the nearest village) are all build in very narrow landscapes, too much mountains arround, no free area.
If you had chosen the other side of the "Wallis" (that´s were you are going to) and there Zermatt, there would have been a good possibility in the small village "Täsch", where you leave your car to travel to Zermatt.
Check out a shop/bar in Saas Fee called "The Popcorn" in the middle of the village. Best place in Town for nicest girls and wildest partys. There are lots of boarder shops in the real nice village of Saas Fee, I think they could be cheaper than in the UK.
If you got any other questions for your holiday, just write me.
Best wishes from Hamburg
Daniel
Daniel.Schulz@Hamburg.de