Bolero is in the non-schengan side. So that is possibly correct.

However I was just in the Fantazja lounge about 3 hours ago and it was indeed very nice. Probably one of the nicer EU ones I've been into. Good selection of F&B, nice and bright. However there wasn't a lot of seating although more than plenty at 1600.

There was definitely a BA logo on the board outside so you should be OK. Just give yourself enough time to get through border control as the queue were a good size when I passed.