All cars need servicing and parts now and then. And having invested so far, starting again with an unknown and probably more expensive alternative doesn't appear to make much sense to me tbh. Although I'm not familiar with the issues so far, I'd suggest sticking with it, cam sensor is a common one, and asking advice here before doing anything often pays 
I know Chris, its just gutting to be endlessly having to pay for something on the car, albeit routine stuff, rather then just drive it and not worry about something else going wrong.
I've spent out on it maintenance wise: 4 tyres, service, cambelt/waterpump/aux belt/cam gasket, LPG service and repair, cam sensor and alternator. The exhaust is blowing, as its been rubbing on the rear axle somewhere and its worn a hole in it, so I need to fix that. I've not even had a chance to fit the nice new interior parts that I bought for it months ago

I'm sure it will be sorted in the end, I just want to be able to get on with making the car how I want it without having to spend out on the oily bits all the time

Claire