Ah I see. Apologies for the inconvenience with this.
Do you have any troubles with on-demand/catch-up?
Which excludes BBC iPlayer & Netflix because they don't use Virgin's catch up system. Julescc123, go to Channel 5 catch up, and select an HD programme to watch. It's one of the only channels that has HD content particularly if you're not on the Full House package and you don't get the box sets, so it's the best comparison realistically.
I've not exhaustively read this whole thread (so may have missed something, and sorry if I have), but... I assume (having never used it), that the PPV movies use the new IP-VOD platform, which is also used by HD-Box Sets & HD-Sky Cinema.
A lot of other VOD content, C5-CatchUp as suggested included, uses the legacy VOD platform. I wonder if the OP has an issue with the IP-VOD platform without realising it.
Virgin Movies still uses the legacy system, as the content is still available on my V+ box which doesn't have the ability to use the IP-VOD system. I suggested Channel 5 Catch Up because it's one of the only channels to offer On Demand content in HD especially if the OP isn't on the Full House package.