We have a Third Party that would like to allow us access to a subnet on
their system via a Site to Site VPN. There is no need for them to access
stuff on our network but they want us to use a small subnet to avoid
clashes on their end of the network ...
Perfect.That did the trick, setup an overload pool with a single address
of the Fortigate IP for the VPN subnet and then turned on NAT for the
Firewall Rule using that address. Seems to have done the trick :)