Ordered some new boots for our A4 yesterday. Goodyear Excellence in 235/45 ZR17 94Y for £85.20 a corner from mytyres.net . They get a reasonable review on tyretest.com. Should be delivered to the fitter next Tuesday so will report after we've had them on for a few miles.
Decided not to go with the F1 GSD3 as they just seem too extreme for a diesel A4.
Conti SC2s are down to under 3mm after 21k which isn't too bad as they looked like they'd only last about 17k. Generally these tyres have been OK and I might have put them on again but they were around £20-25 more per tyre than the Goodyears.