One for the resident experts, just out of idle curiosity as to what this is...

I flew from Gate 23 in LHR T5A recently and when looking over the railing down to the lower floors, a lounge-like space was visible in the corner below.

I'm afraid I didn't take a picture, which would have helped my query no doubt, but it was a smattering of lounge style furniture, predominately brown sofas and chairs with orange cushions as I recall.