Thanks all - I know the previous owner had been using it mainly for motorway driving on the continent but I don't know which one! Maybe the tyres are shot. I will get the shocks checked out too. I haven't tried off-roading on them intentially yet so can't comment on how good they are in the mud!
Jack up car at back and check brakes are fully released! When driving under power the wheels will rotate, but if brakes are sticking, when you take your foot off the gas the wheels could drag on a slippery surface. This will make the car feel very lively.
agree with lazy dog check rear brakes are working properly, done a few now with partially seized rear calipers, it has the effect of over braking on the front causing lock ups. first one I was ready to change the tyres, thought the rubber had gone off every time it was wet or slightly slippery the thing would skid and lock up on the front, very hairy drive. Got the pistons in the rear calipers moving properly fitted new discs and pads, totally diffrent vehicle to drive