Dan I'm not an expert, but is sounds to me as if some sensor has packed up, probably some sort of cold start...any ideas any body?
Regards fuel consumption, I find both my R'handers a bit thirsty, but my new "stock LHD auto" is very good, it only used 1/3rd of a tank from Belfast to Derby. On an interesting note, this cars fuel gauge works the wrong way round! Les, the previous owner, has tried swapping wires around to no effect, he tells he its an "Irish fuel gauge" , mind you, it would fool a car thief!
Chris P