Whilst driving the car hard on a track at the weekend the oil temp went up to 112 deg, but the water stayed at around 94 deg, and the oil pressure was nice and high. Is this sort of temp ok, or do I need an external cooler?

as your oil pressure and water temps were ok i wouldn't worry too much (though as you know am not an expert in BEC's)

I'm assuming it was a hot day? this certainly wouldn't of helped matters....

we've seen higher temps on a car engine when racing...

Ned.