Hi John,
You make a good point regarding the need for a thermostat.

With the benefit of hindsight I would not use a mechanical coolant pump at all. I would remove the impeller and shaft from the water pump and weld shut the hole. I would install a larger Davies, Craig or similar electric coolant pump in the radiator return hose and use the controller to intelligently move the coolant.

I have taken the easy route and am running the mechanical and electric pumps in tandem. By setting the electric pump's controller target temperature 5C higher than I need I am using the electric pump to assist the mechanical pump when the in head thermostat begins to open at 74C, the thermostat is fully open at 80C. The two 5mm holes I have drilled in the thermostat definitely allow coolant to flow when the thermostat is closed as the top hose was nicely warm long before the thermostat opened.

If I remove the thermostat, without removing the mechanical pump, I fear the mechanical pump will prolong warm-up and will over cool the engine under low to medium load.

It was raining today so I installed a grommet on the gear change shaft to seal the firewall and help reduce the noise! One less task on my 'to do' list.