When I was GM 8 years or so ago I used the Number One lounge in LHR. It took them 20 minutes or so for the staff there to decide whether to admit me, even though it was a posted benefit on the Delta website and I had my passport and GM card with me. The lounge itself was OK, nothing great, nothing terrible, and it did have free adult beverages.

I'm not going to switch airline alliances over this. I am going to look at creative ways of exiting Europe and flying back to the USA. I realize that the way I travel is not for everyone, but I had a good time doing it. I took the train (including a rail replacement bus for 20 miles of the trip) from London to Harwich International port station, and connected with the Stena Line overnight ferry to Hoek van Holland, entering the Netherlands (and confusing the heck out of the crack Marechausee at the immigration checkpoint there), exiting the terminal, walking across the street to a station on the Rotterdam metro, taking the train to Schiedam Centrum, then connecting to the NS national rail system for the trip up to Schiphol, then flying Delta AMS-BOS-CLE, availing myself of the KLM Crown Lounge 52, which is almost as nice as the VS Clubhouse in LHR (minus the outside deck and the pool table).

You can also take the Eurostar from London St. Pancras to CDG and fly home from there. The high speed rail also serves BRU. I wish Delta had service from some of the smaller UK airports such as BHX. You can use AF by means of LCY, NCL, EDI or ABX; and KL out of GLA. I'm thjnking about trying a two stop connection to LCY via CDG on my next trip over the pond, just to do it.