"CatchUp" I would take to mean the Virgin OnDemand facility for the 5 main channels, BBC uses their own app but ITV, C4 & C5 use VM's own VOD platform - and you can access this directly from the EPG. Find the programme in the guide, press "OK", then "Watch from CatchUp"
ITV, C4 & C5 brand their programmes with their apps, but you're not using their apps when you play directly from the guide.
If you load the ITV, C4 or C5 app, then you're not using VM's own OnDemand system but the broadcaster's own app - and any issues with that are (at least in the first instance) best reported to the broadcaster.
Is there a particular programme you're having problems with?
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