So, I discovered that the Grenadier is capable of locking itself, with the keys inside.
Having driven up my street to where we were practising bushfire fighting, and therefore expecting to be getting wet, I took the key out of the ignition and left it by the gearstick, and shut the door.
When I returned to the car some time later, it had locked itself. It is not possible that I pushed the keyfob, and no one touched the car in the interim (fully in view). The second key fob is a very long way away.
There is no obvious setting in the vehicle settings to enable or disable this, but most of the 'smart' central locking functions were inactive.
The dealer (who was superb in supporting me, a continuing track record of excellent backup for Alex and Purnell in Sydney) does not know how this "feature" is to be controlled, or if it is intentional or not.
Obviously, don't trust the car and leave keys in without windows open, until we get this sorted.
If it happens, roadside assistance can not effect entry, tell them about the double door seals, and you may avoid wasting hours for that step before escalation.
An automotive locksmith is required, and they will appreciate being told that a Renault type tool will work (I think from vans); the lock may be from the same French supplier Renault uses.
Bon voyage....