Hmmm....
I've had some troubles at Heathrow too. I was in the First lounge at T5 (travelling bus class), - I had accessed the lounge area ok. When I went to eat in the nice restaurant at the far end, they wouldn't let me in as i didn't have a first class boarding pass. When I showed them my CL card, they then let me in.
Whilst sitting in there eating there were 5+ passengers who came to eat and were turned away because they didn't have a first class boarding ticket. IE they were in the first lounge, they were travelling business, their status (wp?) had let them into the lounge ...... but they were getting turned away from the restaurant. The main problem, of course, was the embarrasment this causes the person concerned.
I think that T5 is still ironing out a some wrinkles in the way they operate. Embarrassing the most loyal customers is, I'm sure, a wrinkle that they'll sort out as it's can't be senior mgmt's intention to do this.