Update. It has been all road legal for the last... month or so, and is proving to be trouble free.
Nearly everything is functional, except for, stereo, rear defog, window rubbers, and some slammage.
remove cover from ht-leads/spark plugs,
remove/swing airbox out of the way, unbolt as many as possible of cam cover fasteners, peel back cam cover as far as possible without busting up shitty old plastic.
unbolt sensor without burning hands and/or dropping M6 torx bolt into nether regions of cam cover...
unplug sensor and remove through hole in rocker cover.
reverse is same for install... also, at this point notice all the insulation from shitty opel wiring that has baked/flaked off. Yet somehow the car will still run
20-ish min job. bit fiddly and limited for space tho.
hi-jack over.