Common land was mostly stolen long ago by the Inclosure Acts, and what was left was mostly stolen by the post-war commons registration scheme - if no-one applied to register rights of common they were extinguished after a fairly short period.

Larger areas like Oxshott common have long had statutory or bye-law restrictions on driving on them or camping on them.

As for means tested benefits I've said it before and I'll say it again, benefits should have a gearing to their marginal rate of tax - eg if family allowances were taxed at 2.5 times to marginal rate otherwise payable then those paying higher rate tax would derive zero gain from family allowances - but those below the tax threshold would get them in full.

The government could then save the cost of means testing, since HMRC could do the collecting.