My first question is, are you flying F or B, as BA has separate lounges. I don't remember seeing kosher food on B lounge. Can't comment on F lounge as I don't fly F. Though as I understand you can buy pre-packaged kosher sandwiches from a kosher caterer called Adafina at Cafe Nero.
Thanks for your responses, I was in the concord room and they had hermoils meal available. I dont know if they normally have them or if i lucked out.
You didnt "luck out". Kosher is now available on request at all South lounges and the Arrivals lounge at T5. They normally need approx 20 mins to heat up and prepare.
Otherwise you can still eat:
Some of the biscuits are labeled OU(D)
The Kettle chips are kosher if labeled with KLBD at back (only salted and black pepper are kosher)
The cereals served are mostly Kellogs (approved by Manchester Beth Din)