Sorry User, I'm about 90% sure you haven't got it working in hdmi. HMDI disables scart etc in most circumstances if it is working on the V+. What channel source you got the LG set up on, is it on one of the two HDMI channels? Something like pressing "input" on the lg tv remote (near the top on the left?) and then scroll left and right to various options - labelled AV1,2,3, Composite, HDMI1, HDMI2? You'll need to try selecting HDMI1 or 2. On LGs you can usually rename them so you could call it Virgin or something after you've worked out which. It's an urban myth on virgin that you can't watch BBC HD through scart, you can just not properly.
The V+ engineer did this when I got it installed, plugged in HDMI and SCART and claimed it was set up for HDMI. I had the tell tale giveaway that he'd left the thing in 4:3 though!!! It's not really embarrassing the V+ guy didn't manage to do it or couldn't be arsed here.
To sort out the V+ side you have to press the blue "HOME" button then select "8 settings" and then "4 change audio and display settings". Go to the second line "display format" and the third line. There are various options widescreen and 4:3 are through scart and 720p 1080i and their "widescreen" versions are the HDMI hi def settings plus there are some component settings. Select HiDef HDMI and 720To finalise the settings it will ask you to press a button you cannot see if it's not working properly. This is the TEXT button just below the number pad. Note you may need to suddenly change channel on the tv to HDMI and suddenly all will appear.
You got the volume code for the new tv for the v+ remote?
HTH or that you've worked this out already.
P.S. You can select 1080 but it's less clear for menus etc, this is a bug on the V+.
P.P.S. the HDTV thing on the LCD on the front of the V+ just means that channel or VOD content by source is HD, not that you're necessarily watching in HD.