Just a quick comment on Coopers, (not wishing to start a lengthy discussion).
I have used three sets exclusively on the Tdi 300 over ten years (ST) with a lot of very harsh treatment. Now running ST's on the D3 with nearly 30,000km on them, also a lot of van towing. To date they are wearing perfectly and would have at least 75% tread left. Always found them to be a great wearing tyre.