Longman,
I had the same problem and after lots of under bonnet action I found it was the cold start inlet valve. Top right of the engine - small 1 inch diameter cylinder about 4 inches long. When you turn the key, just on not to actually start, it should make a sound, buzzing sound, only quiet but noticeable. This has two wires coming out the back of it, one of mine had come off, effectively making the car start without the necessary air to enable the auto choke. It may be that it has just stopped working and you need a new one. Hope this helps. :lol:
