1. Well done!
2. Goodyer 4x4 in Coleshill are a very highly regarded Land Rover mechanic, I use them and they are reasonably priced too. Only about 30 minutes from you (A404, M40, off at Beaconsfield, they are on the A355 to Amersham)
3. A decent set of A/T tyres should do the trick; BF Goodrich...