@Richyboy1980 

Hi, even though you change the LAN IP address of the bridge TD-W9970 to be the same network segment like 192.160.0.1, you can't enter the management page of it.

Since the Deco is the NAT device now, your wireless/wired devices can't across the NAT device directly to access the bridge modem's management page.

Besides, the bridge modem only takes effect of transfer the signal from telephone to Ethernet, your Deco devices get internet from the ISP directly.

If you want to enter the bridge modem's management page, you need to disconnect the Deco device and the modem first, connect your wireless/wired devices to the bridge modem directly to check if you can enter.