I have a UK 2002 1.8i Vtec sport and am trying to replace the oil pressure sensor but cannot find a similar to the one that needs replacing..
It's grey in colour, round, has no grooves and has 2 pins. The plug that goes with it is grey also and has a white internal..
Hope this makes sense to someone..

 

I shall move to Genl Tech for you..

Welcome to the HAF..

 

Cheers for that..

 

I'm not sure where I can find parts drawings etc for UK cars.

But one silly thought...
Are you talking about the VTEC oil-pressure switch? It's on the VTEC spool valve, located sorta between the head & the intake-manifold. (And it has a 2-wire connection.) The oil-pressure switch (for the oil warning-light) is located on the back side of the block, just above the oil filter.

 

JimBlake is probably correct, that you're looking for the VTEC oil pressure switch, which is 2-pins.

The other oil pressure switch is only 1-pin, even on UK models.

You can find parts diagram at Lings Honda.