Join Date: Oct 2006
Location: London, UK
Programs: BA Gold, VS Silver, SQ Silver, IHG Plat Amb, Hilton Gold, Marriott Plat, Accor Silver, Radisson Prem
Posts: 16,872
It's ages since I was in the MAN Terraces, so I can't answer some of your questions.
But the lounge is still the original large size (it was the test lounge for the Terraces concept sometime in the late-1990s, and not a lot has changed since). I doubt it would close due to the fairly regular traffic to LHR and LGW, but I could envisage a reduction in size when (if) they get round to renovating it to the Galleries concept.
IIRC, there are showers and you don't need to book them.