LAX_LHR. I believe they were using an A340 out of BHX, which whilst able to go direct, is a lot of seats to sell when competing with an already established carrier using B77Ws.
Maybe an A319/320 ex LBA, after PIA leave, would be a better bet for them than competing out of MAN/BHX.
I have to say I don't think anyone is likely to pick up the route when/IF PIA pull out which would be a shame. After all PIA only came on the route after SHAHEEN showed them where a large part of their MAN pax were actually coming from! It's a real shame they were unable to extend the lease on their A310 as they were growing the route nicely.