We have had a few changes over here (and I think it my be in the light of the evaporating number of air berlin departures from TXL). So basically as TK flights and EW/GW to LHR no longer appear to be using A4 (which is connected to A5 airside behind separate security entrances) then the situation regarding long queues at coinciding flight departure times will have got better.

The trick is actually to manage to leave the lounge just before they call the flight, since, typically, at such time about ten people will get up and wander round to A5 and, therefore, be in front of you in the queue for security!