No bridge (TP-link) to internet (Nghthawk AX8)

Hello All!

I've had a frustrating few days trying to set up my network. I recently moved house and the nature of my NBN connection changed accordingly (from HFC to FTTB). I was somewhat foolishly unaware that my existing router (Nighthawk AX8) does not support VDSL. In order to address this, I got a relatively cheap VDSL modem (TP-link TD-W9970) with the intention of setting it up in bridge mode for my Nighthawk to connect into.

Alas no internet! I should note here that I had no problems at my previous residence.

For the TP-link modem (from factory defaults) I've set it up straight into Bridge mode (no VLAN ID - I'm with Superloop) without amending any other settings, except for specifying the DSL modulation to VDSL2. I should note that as a standalone modem router it works passably and is able to maintain a connection, so I don't think that's the problem.

For my Nighthawk, again from factory defaults, when I try to connect it to the TP-link modem it can't establish an internet connection: DHCP, no VLAN, etc (as per Superloop specifications). I've tried power cycling my Nighthawk through each of the LAN ports on the TP-link modem, even tried different cables and nothing has worked so far.

So, I was hoping people here might be aware of some setting or something (on either modem) that could rectify this situation? At the moment my Nighthawk has become a rather expensive paper weight.