I was in the SkyTeam Lounge in Terminal 4 of LHR yesterday. I was granted admission with my OP Gold Elite card. As I was there just after 4pm, the lounge was set up for "afternoon tea" with a nice selection of foods and a serve yourself open bar.

It's right by gate 10. That was about a 7 minute walk to my CO flight to EWR out of gate 24 (but they do make "flight #19 to Newark now boarding" announcments in the lounge).