Starting issue from Cold

[Challo]

When the car has been sitting overnight, or for a couple of hours to get the engine cold is picks up an intermittant fault. The car starts, instantly dies, then if I turn off the ignition, and then try and start it, it fires up straight and runs with no problem.

The issue started about 6months ago but only everynow and then. Now its starting to become a regular occurance.

Any ideas whats up? Coil packs?

Its the 1.8 petrol astra on a 05 plate.

I would put in the Vauxhall forum but the traffic is very quiet so though the general gassing would give it more coverage.