Ozzy Osborne property plan thwarted by bats

Bats helped cement Ozzy Osborne's reputation as a hell-raising rocker, when he bit the head off a live bat on stage in 1982. Now, however, the balance of power between the rocker and the flying mammals seems to have shifted - as it emerges that his property renovation plans may be thwarted by bats.

But how can they do this?