Hi Sherrardk:
You can't be done for 'liable'; you can only be done for poor spelling ;-)
(Libel)
'Honest comment' is a defence against a claim for libel but "the comment must explicitly or implicitly indicate, at least in general terms, the fact on which it is based"
(Lord Phillips, Supreme Court, December 2010).
So simply writing: "Avoid at all costs, this place is rubbish" could not be defended against a claim for libel as it gives no indication as to the facts upon which it is based.
But (as long as the statements are true) something like this is OK:
"Avoid at all costs, this place is rubbish. We found bed bugs in every room. The food served was consistently 'tepid' rather than 'hot' and the menu was extremely limited . The manager's only response to our complaints was to shrug his shoulders and walk away".
So (again, as long as it's absolutely true) the more detailed and condemnatory you make your review, the better!
Chris