I asked this question before too and there is no definitive answer. There is a BAA plod at a desk at the end of the bridge into the main terminal to prevent people reclaiming baggage and then wandering back up to the lounge. They seem to be very inconsistent about the procedures in place. Phone the Info Desk and ask to have it sent out in writing because I suspect you will be challenged by a very bored jobsworth looking for a reason to say no. Sorry if that sounds negative but that's been my experience.