similarly my partner won an rta case, as she should have, only last week by being brutally honest. if she couldn't remember something she said so rather than bs around it. seems to have done the trick which means £400 excess recovered (yes i know, what kind of policy is that) plus refund due on premiums loaded since.
good luck with it matt. the landlord scenario sounds pretty familiar which means will be very familar to a judge. dont think i can add any advice beyond whats already been offered - lets hope the fella drops himself in it, leaving you with not much work to do
fingers crossed for you mate.