I need to "fake news" myself about the hydraulic tappets. I think they were all shut (drained down?) and I would have needed to whack them down onto a bit of wood to get the piston bit out, clean and test it.
You want them drained-down before fitting the camshaft housings anyway, and they'll pump up as the engine starts.

So, refitted everything and started the engine.....had a horrible metallic noise like maybe another valve hitting something, or maybe a loose screw/bolt/nut having a wild time inside a cam housing!!

Eventually figured out that the dipstick tube had re-assembled at a slightly different angle, and the bottom of the dip stick was being hit by the crank or something in the sump! Panic over.

Engine runs well, headlamp aim motors replaced, just trying to figure out how to replace all the rivnut things the bumper used to attach to ....