Ok great, you will be able to setup a L2TP VPN on this.The red port on the D7800 is definitely the WAN port to which you will need to connect the EE router to. But
before you do this, do a hard reset to remove previous settings and change the IP address of the router to avoid a conflict with the EE router (you said earlier it also uses 192.168.1.1)
After the router has been reset, connect your PC to it, select 'manual configuration settings' once you get the wizard setup screen.
Follow the instructions on page 191 in the D7800 manual (
here) under
To Change the LAN IP Address settings. I suggest you change 192.168.1.1. to 192.168.
2.1 to keep things nice and simple.
Once this is done, follow the instructions on page 74 of the manual under
Specify a Cable or Fiber Connection With a Login and PPTP or L2TP Service .Under
Internet Service Provider choose
L2TP.
Then to test out the free L2TP VPN:
Login: freel2tpvpn.com
password: 3172
server address: uk.freel2tpvpn.com
Hit
apply/save. If necessary reboot the Netgear, hook up the D7800 to the EE router and once you connect to the Netgear it should give you a tunnel connection to the free VPN service. Speeds won't be great as its a free service (i couldn't get more than 15 Mb/s in Win 10 on a 300 Mbps FTTP line) but at least you will know if you've set up the router correctly.
Good luck!
Edited by deleted (Fri 02-Nov-18 11:45:17)