Well back again.
After much ado, and a lot of help (tks Bfit & Sirfixalot) we are at the stage of getting the hoses for hot water, steam/bleed and KC4 oil cooler sorted. I've installed the KC4 return metal pipe, getting into position just missing the steering column. We have deleted the Throttle Body heater and changed that fitting for a 90° unit with a ~8mm tail swetted into it, this will allow manifold water to exit via hose under the "AIR" pump/bracket, under the Alternator, do a left turn back to the Heater Matrix in the fire wall, whilst a new hose will allow the steam/bleed to be drawn into this water flow.
A new hose from the Heater Matrix will return heater water around the radiator, under the A/C and into the Water Pumps small side inlet, but I need to dream up a fitting that is like a "Y" or "T" junction set in this hose right before the water pump and will allow the suction of water from the metal pipe (KC4).
My 87 or 90 dont have water taps either manual or vacuum in the cars heater cct, and I cant see any reference to taps in any FSM's or Youtubes , I'm assuming that the HVAC (Heat Vent Air Conditioning) uses a combination of hot matrix mixed with a cold evaporator to obtain passenger set air temps.