Mytyres.co.uk (prices seems dependant on stock/availability so you'll need to check) .
Yup fitted them myself (see I Haz thread in XT660z tyres section) but to sum up, very stiff carcase but it was subzero at the time, I pinch flatted the rear tube and the alloy rims mark very easily.
I also had the assistance of my tyre/wheel stand