I spoke with a tyre fitter and confirmed the following:
1. Legal limit is 1.6mm, but it is advisable to replace your tyres when they are down to 3mm.
2. My tyres had plenty of tread left, however they were dangerously worn on the inner side. The tyre fitter said that the 3mm or 1.6mm rule does not apply to that part of the tyre, they are still legal so long as the tread is still visible. Sadly, that was not the case with my car, hence I had to replace them!
3. My vehicle's allignment was optimised and it did not contribute in the tyre's uneven wear. The tyre fitter said that car manufacturers tend to design their vehicles having in mind the "bread and butter" models of the range, which in the case of the GP are the 77-95bhp vehicles, the 130bhp Sporting was optimised for handling, ride and tyre NVH, but not for tyre wear
I do understand the 1.9 JTD is a heavy lump, but I do not drive like a loony! I am working in the construction business and travel a lot, my daily commute now is 130 miles daily, Swansea to Haverfordwest and back, I accelerate smoothly but on 3-4 occasions I put my foot down to overtake.
I would very much appreciate if somebody advises of a tyre make for the JTD Sporting that will last longer than 9,000 miles, because those tyres are expensive and the way things are going I'll end up replacing them every 4 months!
Sometimes I miss my Mk1 1.1 punto, £96 would replace all four tyres including balance and allignment!!!