Two possibilities - ARB (anti roll bar), or drop links, or maybe both (is that three possibilities then?).
You need to get the issue sorted as any of the above will result in a fail and a waste of money.
For an idea of prices, ARBs are £65 and a pair of drop links is around £40, both from a dealer. Changing them is around an hours labour for a garage with a lift.
Cheers,
Mike