Sounds like something to do with PATS - the Perimeter Anti Theft System. I don't know about the WS/WT Fiesta, but I know the WQ has the same system as the BA/BF Falcon/SX/SY Territory, in that there's a mini rfid like transponder in the key, that is 'excited' by an inductive ring around the ignition keylock to activate and transmit a code. The keylock receives that code and then sends the value in the key to the body module, which then sends it on the
CAN bus to other modules so that they 'unlock'and allow the car to crank and start. Putting in a correctly cut but uncoded key into a BA falcon, it will crank, but it won't fire.
Is that your symptom? Crank-and-no-start? Or on the quick turn attempt is there just nothing?
Luke