Immobiliser issue?

[B300ABT]

It must be that time of year again.....
On Tuesday, my partner drove her A2 a mile or so to attend an art class. After two hours, she came out, started the car - and then engine just stopped after a second or so. Tried several other times - fired up, repeat performance.
Got the AA out, and they couldn’t do anything other than tow her home.
I disconnected the battery, left it for 24 hours in order to achieve a hard reboot, reconnected the battery, geronimo - all fired up and raring to go!
This is the second time in 2 years that this has occurred without any prior warning. Any bright ideas as to what the issue might be and how to solve it?

 

[timmus]

Hello,

If the immobiliser is responsible for the engine stopping, then the yellow key symbol in the instrument cluster will flash. Knowing whether this was or wasn't happening is therefore a critical piece of diagnostic information.

Cheers,

Tom

 

[B300ABT]

I wasn't aware of any warning lights flashing. Interestingly, I noticed that the pre heat coil light wasn't working, and it had thrown up an ECU warning light. Now that it's running again, pre heat coil light is back and ECU warning light has gone.