Unusual tyre wear

[bobdabuilda]

My front tyres have really worn on the outer inch of tread on the continental uhp cross contacts so much so that theres hardly anything left of the tread on this part of BOTH front tyres. The rest of the tread across the middle and inner portion is 5mm.

I took it into National tyres centre yesterday and the resident 'halfwit desk monkey' tried to BS me that my tyres were illegal and that the tracking was obviously out. I replied that as over 75% of the tread on the tyre was 5mm they were perfectly legal and that the car had only been tracked within the last 6months. He then changed tack but still made out that the tracking would definitely be out- long a short of it was that the tracking was 0.5mm out when checked. He said there was no point trying to balance the wheels as this wouldn't cause that problem. Luckily the lad doing the garage work was more clued up than the desk monkey and it didn't cost me anything but did advise getting the camber checked at the Volvo dealers. It's a shame that the tyres can't be flipped on the alloy(due to their inner and outer fittings) but I may switch the back wheels which have 6mm and even wear, to the front- any thoughts on this?

The wheel bearings are fine and the trackrod ends i have yet to check. It had a new propshaft fitted by the stealers in April and the wear has only really been marked since then so could this be the cause (unlikely to me ) but is there be anything else I need to check out?