Skoda Fabia Immobiliser Issue - Solution

Got it sorted. Long story short; after 2 weeks in the garage, with the mechanic trying numerous things, he found that the engine would start if a secondary electrical feed was provided to the fuel pump, but with a continuous feed it wouldn't stop when the ignition was switched off.

So he wired it through a push switch fitted under the dashboard.

The switch has to be in the on position to start the car but switched off once the engine is running.

I thought I would post this just in case it may provide a possible solution for someone else who may have the same problem