I have been using a Netgear D7800 modem/router but my internet kept dropping out every few days, so wanted something more reliable. I had heard good things about the Draytek Vigor 130 so bought one, after a bit of faffing i got it set up and connected to my D7800 (BT infinity 2 FTTC).

My question is, is there any way at all i can access my 130 to view my line stats via the router or remotely? I do not want to have to keep unplugging the Ethernet cable and plugging it directly into my PC to access the 130's web interface.

It depends on the functionality of your D7800. (Not that it helps, but you were using a Vigor router, then there's a feature available to do exactly what you want already built-in.)

In generic terms, you'd need to have a second (virtual) interface on the WAN side of your router which can address the LAN port of the Vigor 130. I'm not sure a consumer piece of kit like the Netgear D7800 can do something like this, but I may be wrong.

Here's a guide for doing this with pfSense (a fully configurable firewall/router solution) which might help, assuming the D7800 has the capability to do something similar

https://www.netgate.com/docs/pfsense/interfaces/accessing-modem-from-inside-firewall.html