Well, I used the PX8 and Creative BTW4 pairing today, quite a bit (listening to them now, connected to my Macbook Pro). The Creative has been connected to my S22U, Ipad Air and Macbook Pro, all without any real difficulties. There has been no loss of signal and the Creative is glowing purple to show APT-X Adaptive is engaged. Works very well. Train journey of nearly 4hrs 30 mins - very impressed with the SQ and noise cancelling abilities of the PX8. No jumps or shudders, despite the train doing both. Warming to the sound signature much more than my first time of ownership - enjoying the luxurious sheen they give to female vocalists in particular.
It is annoying that the B&W Music app currently does not display the codec that is being used (something the FOCAL app does, and something the older B&W headphone app did, at least for the Pi7s). Hopefully something B&W can add in a software update. Also, my PX8s are showing software version 1.0.0., suggesting there has yet to be any firmware updates for the PX8 (only mentioning it as I noted that the Bathys was on v1..4.sth when I returned them).
One bit of related news (at least here in the UK): the Pi7 and Pi5 s2 are due to go on sale tomorrow. I have received an offer code as a registered owner of the original Pi7s to buy a new pair at a substantial reduction. Key features, from what I can tell from the email are that the S2 uses the Music app, now have 5hrs battery life and quick charge of 2hrs from 15 mins charging, a better antenna design for connectivity and some new colour options (inc midnight blue). Tomorrow morning (when they go on sale) will see whether I am tempted to pick them up. Apologies - can't share the code as it is a single-use, single unit code as per the B&W email.