Right then - here's some video evidence !

2 problems with this, but the second one is unrelated to this discussion, so probably warrants a thread of its own, or will get added to my last post about 4k workflow.
Here is a relatively unedited whole flight, with some telemetry data overlaid so we can wonder at what the **** that barometer thinks it's doing ! Starts at 0 ft on power-up, then at motor start begins a steady descent to -18 ft before the craft has even moved, and continues doing that, even as the craft launches, in what I would very much describe as 'the opposite direction' ! By the end of the video it is a whole 40 feet wrong, which is really no small error !!
I do note that sort of thing all the time, and can honestly report that I have never noticed the drifting at anything above 20 or 30 ft - it's almost always at near ground level, and usually only at the very end of a flight, as I come in to land nice and early, with 14.7v on the pack.
Always do, and this time was no exception - sticks tested fine and got stirred before the session.
I'd say I was at about half way. I had launched in full rabbit mode, and stayed there until the cinematic panning bit in the middle, for which I dropped it to half way, and then as far as I remember left it where it was after that. I would expect that to bring it down a little slower, but what happened here was a literal 'stop' in which the descent I was doing went from -10 or -15 ft a second to 0 ft per second - you can see this at
8:38 in the video, as the craft reaches what it is reporting as 30 ft (but which was actually more like 50). At this point I released down throttle, put camera back in heading mode, dropped landing gear, and then tried full throttle down again, which produced my final, incredibly slow descent.
Despite the effort I appear to be putting into trying to find out what is going on here, it remains a relatively minor problem that I feel I am relatively well-equipped to deal with on the rare occasions it happens, but I do wonder if I have a faulty barometer, so just trying to guage opinion on that...
Thanks for continuing to listen guys