Help required to get external display working via USB-C/Thunderbolt on T480s?

Spec: T480s, i7- 8650u, Intel HD 620, Has two USB-C Ports on the left side.

Problem & steps I have tried so far:

• When connecting to an external monitor (Lenovo P49w-30) The screen recognises thunderbolt has been connected, but does provide any video signal.
• USB-C works for other devices, just not monitors (would it be USB Map related?)
• I have followed the Dortaina Framebuffer guide with Whatevergreen suggestions
• Also the Hotplug Kaby Lake Guide in Dortaina as well.
• My next option is to try another monitor with USB-C/Thunderbolt and see

If anyone has any clues to advanced knowledge of this particular T480s spec and how to get this to output video, it would be much appreciated.

Thanks.