LY moved back to the center stem of Terminal B (Gate 55 I think) after being kicked out of the BA lounge. Hence, even if you could access the BA lounge, you'd have to go through security twice - once to the BA lounge, then back out and in again to the LY gate. LY has its own "lounge" at the Marriott hotel to and from which it runs a shuttle. Rumor has it that they'll be taking over one of the existing Terminal B landside lounges during the first half of 2009.