£113 - well over the odds dave IMHO and experience. I've had my Croma of full 4 wheel alignment at least 3 times and still paid less.
Anyway......
Your figures, especially rear negative camber are very interesting. It is VERY rare for any Croma to get anywhere near -1.5deg negative camber in my experience.
With only -1.5deg you should get at least 30K miles from you rear tyres.
As I have said before in other posts Fiat/GM have some very strange repeatability, tolerance variations. Seems to me that every Croma has/gets different rear suspension setting tolerances/ranges.