Hi we use this system from Kamtec
http://www.ebay.co.uk/itm/IRACE-I-ra...item2c6dfe6cbf
It works really well. You don't have to buy the whole system you can buy enough to get you started for about £300.
Our club is not far from you. Its near Ottery St Mary. We are racing on Wednesday evening. You are very welcome to come and have a look at the system.
Great news about the track