Well, against your advice V6 junky I went ahead with the Forte
flush. It's non acidic and is used by the local Alfa indie (ex Alfa Romeo UK mech).
Went and added it and ran the motor at idle for 15mins. Drained the spent oil.
Cursed and hissed as I had to move the oil pipe brackets to get at the filter, eventually got it out after a period considering it an impossible space to fit through.
Refilled with semi synthetic and ran the car for 15 mins again at various speeds including the recommendation on the sticky link for the VLA.
Drained the oil again, and removed the filter. The oil was pretty dirty looking, still black.
Installed new filter and refilled with Millers CFS 10w60, and so far good news, no sticky tappet (but I bet it'll be back).
Now i just need to replace the corroded water pipe at the bottom of the radiator, and refill with Paraflu UP. Picked up the replacement from parts dept today.