TXL in 1999. And I wasn't even entitled to lounge access!

I remember it being a greyish room which you entered with a PIN code (probably wasn't an actual BA branded lounge in fact). Some colleagues were travelling in CE (these were the halcyon days when some could book CE without anyone battling an eyelid) and let us in. We made a quick exit when someone came around checking boarding passes.

I actually missed out on the lounge on my first trip in 2000 when I was properly entitled to access because I was delayed travelling to the airport and had to go straight to the gate.

First proper visit of a BA operated lounge was GVA in 2000.