To give myself a break from drinking and because I needed to stretch my legs, I left early and wandered over to the JL F lounge en route. This is by far the worst of the 3 OW LHR T3 lounges. Limited drinks (champagne was Moet & Chandon mini bottles) and food, no computers, no showers. It was, however, open from 1300 according to the sign on the door rather than the 1500 listed on the OW website.
I thought about also visiting the Servisair lounge, but by now it was close to boarding time so I went to the gate instead.