Intermittent non start related to central locking

[Wayne M]

First time post.

I have a 2009 XJ. Last of the old shape.

99 % of the time it starts no problem.

1% it doesn’t.

The time when it won’t start I know before I turn the key. The central locking (either by using the fob or the key) only opens the drivers door and the car remains immobilised.

it won’t even turn over,  just get a clean click when I turn the key. Steering lock remains on.

If I open and close the lock on the drivers door manually from inside enough times,  it eventually fires open all the doors.

once all doors have opened the car starts no problem.

Alternatively if I leave the car and go back to it a while later more often than not it will start ok and the central locking is working again as normal.

I can use the car for days or even weeks before it happens again, but again I know it won’t start if only the drivers door opens.

when it’s in the immobilised state the boot will not open withe the fob, only with the key.

Car has been into two independent garages and they cannot find any fault, but then the fault hasn’t happened whilst they have had the car..

Any ideas would be much appreciated.