I had the same problem on my Disco. Turned out that on of my tyres... remould off roady things... had not worn evenly so some of the lugs were more worn than others... this meant that the tyre was no longer perfectly round resulting in serious wheel wobble.
Best way to check would be to lift the wheel off the ground so it clears by a milimetre or two and then spin the wheel. If it scrapes the floor it has an issue.