Got the tailgate release working again. Button does nowt when the little plungers in their clear rubber housing have somehow dislodged deep inside the white section of the switch. Temporarily caught out by the power having stopped since car had been unlocked so long, until I pressed the unlock on the remote and the tailgate button sprang back to life.
Got the tappets, pushrods and rockers all back in. Just within tolerance for pre-load both sides, top of range one side, bottom end the other. But all OK.
Rocker cover paint, fuel rail finishing and broken inlet manifold / fuel rail / loom mounting bolt to sort, then it can all be buttoned up snug. Hoping for MOT this month, first week in December at latest. And that typing that doesn't jinx it all!