I often find this too. The catch up service seems positively skeletal when you actually try to use it and find out how little you can access in what seems like a straightforward manner. Not only that but the pages seem to take so long to load it leaves me wondering if my download speeds are all they're cracked up to be. I am on a Big Bang bundle. Can't even watch Code Black on tv anywhere without upgrading either... Apparently. Although there may be some kind of service malfunction in my area that is leading to this message. In which why does it ask me to upgrade benefitting Virgin only???!
However back to your problem... I often find that simply logging into itv on line or chanel 4OD using a lap top means you can access far more of a back log of tv for those channels and if you then plug your computer into the tv via HDMI cable - you can watch it via the screen usually getting sound from your computer only sadly... It is so disappointing to feel like you've been promised a feast of catch up tv and tv anywhere but when you actually try to view it it either isn't available, seems to require an upgrade of some kind which (when like me you're paying £75+pcm to Virgin all told) seems a bit scandalous.
Good luck and take note Virgin, my patience is wearing thin!