Houses are purchased upon vacant possesion on top of this there will be a fixtures and fittings list.

If on the fixtures and fitting list it lists things like:
Cart full of shit
Garage full of shit
Dirty old carpet.

He's unlikely to get anywhere, if however this isn't listed the solicitor may help.

For future reference when buying a house I would be going to view it a few days before completion to make sure everything is as it should be. This is what I did and made sure that the previous owner got rid of all their crap.

J