Seeing lots of comments about tyres I have just fitted a set of General Grabber AT tyres (205, 75, r15) and I am pretty impressed so far. They have a good fairly aggressive tread pattern and only slightly noisier than the Duellers that came off.
No serious mud yet but they should do the job.
Tyres supplied by www.event-tyres.co.uk who were very efficient. Fitted by mobile fitter at my office at cost of just over £300 for 4 tyres.