You have my commiserations. Little can be done in your circumstances, unfortunately they are a thriving species, much to the misfortune of hedgehogs , farmers and gardeners.Its likely that they are hungry this hot summer. Perhaps you could feed them off site? , although this is supporting the problem ,really.
You may be able to co-operate with members and your council. Perhaps the council would provide chainlink fencing if you could arrange to install it.
See :
http://wildpro.twycrosszoo.org/S/00Ref/bookscontents/rspca-problems_with_badgers/6_Damage.htm
Cleansweep
