That looks like a good little setup you have there. Yeah totally agree with you regarding the idea of fan switch feedback. That's why I was a bit confused by some of the things that I was told by the shop where I was going to get some bits. They seemed to be saying that the 'fan control system' was looking at engine coolant temp (an actual sensor) and also the fan switch temperature - suggesting that there was feedback from it. I wanted to change to a lower temp fan switch in the belief that this would by way of a dumb switch just turn the fans on earlier, but they said this would confuse the ECU and that the engine coolant temp sensor would just override the switch anyway as though it were some kind of master signal. I then did a bit of reading and found that there seemed to be multi pin plugs for these fan switches so I started to think that maybe they were right and just parked the idea.
I'm just going to instal an 82 degree (cracking) thermostat if I can find one locally, put in a switched bridge on the A/C pressure switch to use that fan for auxillary cooling and leave the rest alone I think.