Thanks Tom, that puts my mind at ease a bit re ride height but I am still going to pursue dropping it down to roughly your original heights.
I've had a good talk to my mechanic and taken some measurements and I am going to get the diff housing re bent to 1 degree negative camber. At present it has just under half a degree and after measuring the front wheels which are 4 degrees negative, from the bottom edge to the top edge of the mag is a difference of 28mm so divide that by 4 equals 7mm per degree.
There is already a 3mm difference between the bottom and top edges of the rear mag which lines up with the half odd degree of negative that has already been pressed into the diff housing.
So assuming I have got this about right there should be a gain of 4mm with the extra negative and I have just had an engineer friend of mine look at the mag and he's comfortable that he can safely remove 5-6mm from the inside so that combined should give me around 10mm of extra clearance which should do the trick.
Interestingly when looking at the right rear tyre the inside quarter is clearly not really doing much so some more negative should help there. (does seem a bit odd but again if the car is leaning over...)
I will also have to remount a new rear sway bar most probably coming off the spring platforms but I think that all this should be relatively easy.
If that doesn't help it then I give up!
Re the tyres going off- the rears were new and definitley did not seem to offer as much grip as the worn ones that came off.Most people that I have spoken to here talk of the Kuhmos lasting a season with ease if rotated and they generally get better as the tread starts dissappearing.
You would'nt be able to post a picture of the Addco bar by any chance? I'm just trying to get my head around how that all fits up.
Cheers
Dave