<font color='#0000FF'>Gareth,
Basically all you need is a DPM (Digital Panel Meter) or old multimeter, 10 turn Pot, a few resistors, project box and a 02 sensor. You can get all the parts from Maplins, RS, Farnells etc for about £20 excluding the sensor. I like yellow things tho so I'll probs go for the analox
