Coming back to this, after a few sessions struggling to get paddle ups on the AFS Ultra 750 in light wind bumps, I did what any sensible person would do and put a strip of grip for my front foot as a reference point.
Turns out my front foot was way too far forward, and shifting forward, for that foil, and this was preventing my paddle pumps from causing the foil to lift.
Properly trimmed, the paddle ups became pretty easy.
I’m certain that poor trim is the root cause of most paddle up and pumping issues.