You're not missing much by not getting access to it ... As we all know Admiral's Clubs aren't exactly the best lounges .. and the MEX one is far from a shining example thereof ... IIRC you get drinks vouchers if you're on the BA flight so at least you dont' have to pay for a drink (apart from the intimitadory looking tip jar in the middle of the bar ) ... Not worth arriving in the airport early to avail of the Admirals club facilities ... it's also a looong walk from the BA gate when I used it (not sure if this is always the case)