An update. I can now access the NVR remotely, and it is being detected on the network as wired. At last some progress has been made!

@kevin_Z These are the results of the Ping to the main hub when the NVR is connected via an ethernet cable. Pinging 192.168.68.1 with 32 bytes of data: Reply from 192.168.68.1: bytes=32 time=4ms...

Thank you @Kevin_Z Many thanks indeed for your reply. I really struggle to understand how IP's and Gateways work - I've watched many videos trying to learn the basics, but I can't grasp the concept...

I've recently puchased a three hub Deco M5 system and set it up without issue. However, when I hard wire my NVR (digital recorder for CCTV) it does not show up on the network and therefore I can't...