After months of trying

i have now found the Virgin+ code to enable volume control on a V+ control for LG 50" PK350 = 1 7 6 8
➊ Press *(STAR) + and TV together on the remote for a few seconds until the TV light on the remote flashes twice
➋ Slowly enter digits 1768 the remote light will flash twice again
➌ Point the remote at your set-top box and test the volume buttons.
Hope this is of help to someone.