I just had a full set of Cooper Discoverer AT3s fitted to the Mitsubishi - £112 each and initial impressions are very, very good indeed.
We run AT3s on our Freelander here in Oz, and we use them off road a lot. They're not the best in mud (but they're not a mud tyre), but seem a pretty good compromise all round. Lower economy than the contis it came with, but that's to be expected as they're a road tyre. Only niggle has been holing one on a gravel road, when I would have hoped it would have stood up better, but been many thousands of kms since then without a hitch.