HG659: Accessing a locally served website via public address

In Dunedin and newly switched work connection to Vodafone. I have a locally hosted website, and want to access it directly using the same URL from in and out of the office.

On the previous router (Orcon NF4V) this worked by default, but the HG659 doesn't do the same routing out of the box. Can I configure it to do this?

I have a site foo.example.com

Public DNS exists and points to my external IP

I want to access the site from inside and outside the LAN (using the same URL)

Old router: worked fine. HG659: times out accessing foo.example.com when this resolves to external IP. foo.example.com is accessible to external devices.

Could work around it via DNS (resolve to LAN IP for clients requesting from inside the LAN) but I'd prefer to not have LAN-specific DNS settings if poss, so making the router work as per previous would be ideal.