I shall be honest. My RST is fine on the move but it is reluctant to cool down upon hitting traffic for a length of time. It will not get hotter but it will not cool down either. The fans come in with the gauge a little beyond 3/4 (it is still within the white but not far away from the black line near the read). I shall do a thread about this, but I do know a few things of the car

It's running a genuine Ford Puma thermostat (82 degrees) with a jiggle pin at the top - It did not run a stat prior to me owning it
Genuine Ford 10 year coolant mixed to a 50:50 ratio
Samco hoses throughout
Direnza radiator
New heater matrix
Stage 2 T3 turbo (stock turbine but .55a/r compressor with ball bearings)
Two bleed off pipes to the header tank
ZVH 1.8 on MFI with a 5th Injector running on the rich side (11-10:1 AFR).
Fans on the front of the radiator radiator with a Pace chargecooler radiator in front of the rad (it is around 3/4 the size of the radiator).
225BHP

At the moment the only thing I can think causing it to be slow to cool down (i.e ages unless you turn the car off (fans still run) then it does cool down quite quickly!) are

Iffy radiator but the car is fine at speed
High RPM ; it idles at 1400rpm even when warm ; I need to check the aux valve is not leaking or the hose going to it ; are the latter available from anywhere?
Lack of sealing around the radiator ; it has loads of gaps around the front of the car!
Crap fans ; they are of the SPAL variety (twin fans).

I was considering sealing the radiator off with flashing tape or something more decent looking (ideas?) but I would rather not risk it with an exposed cambelt ; I really need to work on getting the cover made up for the lower half of the engine.