Thanks MrG, I've updated my profile.

We only have 4 CO lines into the building at the moment, so I'm not sure it would be an option for us to permanently assign one of them to do the external forwarding. Although we may be able to purchase an additional line card for the KX-TD816.

Now you mention it, we do have a KX-TPV100E sitting next to the PBX. It was recently thought to be defunct until we repaired it's hard drive.

Would it be possible to divert unanswered calls made to the hunt group to the outside line via the VPS somehow?

Any advice would be very much appreciated. Many thanks.