Cutting out immediately after start up

[DAKOTAstorm]

Ran the Tuscan to the shops, 20 min run down the motorway, everything ran fine. Upon returning to the car it started up fine, ran lumpy, I was able to move about 25 yards, then it cut out. When trying to re start, ignition comes on, fuel pump primes, engine starts and turns over then immediately cuts out. Same when throttle open. Fuel is in tank and battery fine. There are no fault codes. The speedometer has not been working, don't know if that could be related just giving all evidence. It's a mk2.

Any ideas? I am currently still in car park awaiting tow truck but thought someone may know the fault and how to correct it.

[DAKOTAstorm]

Miraculously after sitting for an hour in the car park waiting for tow truck, out of boredom I gave it another go and she started up and off I went.

It had been sat for two days, in the rain, which it doesn't like at all, but driven to the shops where I was stuck. Hopefully she will start up this weekend and I can give it a long drive home and fix the speedo problem and fit new battery.

[DAKOTAstorm]

I do not know about the spark plug cover I will have a look this weekend, but then it was starting up and firing. If the spark plugs were at fault I'd have no spark to kick it in to life?

The fuel pump was priming, usually when I have a fault with the immobiliser it shuts off fuel circuit and it won't prime.

I did originally think water had gotten in somewhere and the hour I had sat and previous engine temp was enough to dry it off, but then why would it start originally to drive to the shops. Has me baffled.