[Spiny]

This sounds like a flat 12v battery.
In theory the drivers door opens with the manual key, you can then open the bonnet (or tailgate from the inside) and jump start or charge / change the battery. Under the bonnet are the connections for jumpstarting, the battery is under the tailgate floor.
There is note in the manual about the locks :-
Lock cylinders
Designed to free-wheel if they are
forcefully rotated without the correct
key or if the correct key is not fully
inserted. To reset, turn cylinder with
the correct key until its slot is vertical,
remove key and then re-insert it. If the
cylinder still free-wheels, turn the key
through 180° and repeat operation.

If you haven't already seen it this thread describes opening the tailgate with a flat battery but you still have to get in.

 

[Spiny]

Thanks Spiny, we wondered about the battery and happy to change it. Which then leads us to -how do we get in? See your note on lock free wheeling- it isnt (life is never that simple!) So can anyone help us with suggestions about how to get in the car? Thanks

The key is mechanical and is intended for this circumstance. Is there any chance the lock is frozen? Pure speculation but if the area your in has a hard frost you could try warming the lock area (hot water?) Otherwise do you have a breakdown service like the AA/RAC?

 

[Spiny]

Great to hear it's up and running, next I guess is the mystery of the keys which needs solving at least for piece of mind .