Virgin Media TV - 'Channel failed cs2004'

TotesRandomer

Hello friends,

I’m on Virgin Media 360 (TV and http).
Accordingly, I have the 360 modem and tellybox.
The modem has the option to be switched to modem only mode.
So here (was) my cunning plan...
I was gonna switch the 360 modem to modem mode and hang a dd-wrt modem off of it so I could set up a vpn tunnel exiting in the UK for BBC iPlayer.
So I switch the modem to modem-only, attach the dd-wrt and set up an SSID the same as the one on the 360 modem.
At this stage, all is going swimmingly but I've ran into problems with the TV side of things.
This stuff used to be food and drink to me but seven years ago I survived a brain injury so, as much as I hate to admit it, I lack the concentration needed to do this stuff properly these days.

At this stage, I'm not sure I've even got the cabling right?!

I have only one cable coming out of the Virgin wall socket going into the router is this right?? Only one?!

I've factory (pin-hole) reset the 360 router and Internet is perfectly fine but the TV is wonky. The TV guide is there but any time I select a channel I get 'Channel failed cs2004' but I can watch certain existing recordings so the basic wiring is okay I think.
Any hints, clues, ideas suggestions, advice gratefully received, the mrs is pissed off :(

TotesRandomer

D'oh!

The relevant Virgin TV cable wasn't plugged into the tellybox. :