Thanks for input chaps, I will get back on it in the next few days and take a look at those suggestions.
The headlights earth you suggested @winthattt - I've removed head light connectors and sprayed contact cleaner but the earth for the headlights, where do I find this?!
Topics relating to the Lotus Exige S1 (series 1)
I’m not sure where the front headlamp ground is. In the two pictures you can see where the main front earth point is, I expect it ends up there. You can also see the clamp wiring and the connector which must have the ground. It’s the earth to the chassis that must be good. I would not expect clean inside a bulb holder to help but it was worth a try.