I've managed to get 2 guests into the Flounge at LGW. I asked very politely at the desk whether there was any chance the second guest could also join us in the Flounge (he was otherwise eligible to enter the Jlounge). The fact that he would have been in one of the lounges either way (the Jlounge was quite busy IIRC) may have played a role.

I certainly wouldn't expect it to happen again though. I look forward to being able to do so 'officially' once I become GGL.