GTA Air Conditioning valve location

Hi All,
My GTA is now at the Auto Electrician having a few things looked at.
We are unable to locate the AC valve which is used to fill the system. The book says it is at the rear near the compressor but so far we have not been able to locate it. Could someone point me in the right direction as to its location.

Many thanks,
Paul.

[BIG_MVS]

I guess it's a UK supplied RHD car? If so the AC would have been retro fitted and not as per the manual. Have a look around the drier (front left in front of the wheel) or under the scuttle tray.

Actually it was delivered new to New Zealand and imported to Australia 12 years ago. The AC is factory.
I thought I saw it at the front when I replaced the radiator but not so sure now. I'll keep looking.