Help Getting ZyXEL WiFi phone to see the outside world

Hi,

We have just changed our network setup, and our ZyXel Wifi phone now doesnt work anymore. It seems to register but cannot make any calls, it appears not to be able to get to the outside world, but can receive calls fine.

Our setup is as follows:

192.168.0.254 - Dlink Modem/Router PPPoE (Mikrotik in DMZ)
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192.168.0.2 - Mikrotik (Interface 1)
192.168.1.1 - Mikrotik (Interface 2) - Also Running Hotspot
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192.168.1.254 - Dlink Access Point
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192.168.1.200 - ZyXel Wifi Phone

Unfortunately we cannot change this network setup for a few reasons, I am guessing I can get it working if I get a correct srcnat/dstnat happening, but I cant seem to make this happen.

Any help would be appreciated.