Well, Rob, there is a need for a lot more information to be able to help ... like ..
-what MT router ?
-what is the configuration? Gateway (Home AP) or just access point ? It depends on details, so the file yourfilename.rsc created with "/export hide-sensitive file=yourfilename" should be attached.
-using the WAN port on the MT?
-got a DHCP address lease on that WAN port ? Or did you set it manually? (IP address/netmask and then added default route to gateway, and a DNS server?)
-can you connect (ping) from the MT to the Internet ?
-does the client get an IP address and default gateway and DNS ?