Oh well - you were all right, of course. Just started a new TR block with a ramp test which gave an FTP of 243, so significantly over the last one. Surprising, as I haven't done any structured training over the last few weeks - just a couple of longish rides and messing about with VR apps.
I think some of it has to do with getting used to the ramp test itself. This time I made a concerted effort to slightly accelerate into each new level to avoid the sudden "drag", and of course the ear-bleeding tunes and caffeine.
I've long given up on the IQ2 debacle, so fitted a 4iiii left power crank (black Friday deal) to the Van Nic, so both road bikes now show power, which will make the coming year more stat-filled than ever
EDIT: I can confirm that the TR sessions are considerably more "challenging" since the increased FTP