Right guys, well I think in light of the advice I've received, it would be best to first sort out the resistor and hopefully that solves the problem. If not then I'll have a look into the thermostat replacement.
Regarding the firing on all cylinders issue, I'll make a note of the aforementioned possible causes of the problem and talk to my mechanic.
I'll be back in touch with everyone on the thread as soon as.
In the meanwhile, thank you all so much for the help and support
