Agree an allowance would be a sensible way to go about this. But given that, as far as I can tell, most of the motivation for an LVT in the UK is some variant

Agree an allowance would be a sensible way to go about this. But given that, as far as I can tell, most of the motivation for an LVT in the UK is some variant of "stick it to small private landlords", I think it's unlikely.