Thanks both.
The first problem is that something is wrong with the driver's door mechanical locking mechanism. Inserting the key just doesn't unlock the car, unfortunately, and I don't know if there's another keyhole on the car, but I don't remember there being one. This has been an outstanding problem which I told him to get fixed last year. Now the cows have come home to roost and he is up the river without leg to stand on.
In the end, he opted to break a window as he really needed to get to work to complete a 2 week job and get paid. He as got a replacement lined up for the window but it is £100 plus VAT supplied and fitted. Expensive lesson but one I hope he learns.
And he still needs to get that door lock fixed and also get a replacement second key as the remote on that is kaput.
Thanks again for the help.