You were a lodger and not an (assured shorthold) tenant, so the tenant wouldn't have been required to protect your deposit. Nevertheless,
the guide jointly published by the 3 deposit protection scheme companies should provide you with some guidance on what the landlord is and is not entitled to.
Per the guide, the landlord is not entitled to betterment, which is what I would suggest charging for the full cost of the tabletop would be. It is also still usable, which make replacement unlikely to be justifiable. So the landlord is basically entitled to compensation for reduction in value taking into account fair wear and tear.
Practically, since your deposit is not protected, your recourse would be discussion with the landlord to come to an agreement both of you can live with. Failing that, the small claims court.