I'm not surprised places aren't willing to fit tyres they haven't supplied. Theres plenty out there who will be looking for damage to a wheel (a small scratch etc) to be rectified if the tyre fitter makes a mistake....for €10 or €15 a corner isn't really worth the effort for anybody. Big risk for little return (in proportion to the money thats changing hands).

I recommend camskill anyway. Fast delivery good stuff and great prices. Being honest though if you are so fussy about the wheels I would recommend buy tyres and get them fitted at the one outfit at least they will be willing to sort out any mistakes.