Hi @cass thanks for your post here in the Community, hoping you are well.
As the app isn't Virgin Media owned, we cannot support on this unfortunately.
Of course, there's no harm in trying but we can't suggest either way if this will work. What might help before you buy one, is to try casting the Sky Sports app to your Smart TV via a wireless screen share that most Smart Phones/TV's have?
This way, you'll know whether or not casting works before investing in a USB-C to HDMI Cable.
I hope this helps.
Many thanks
Tom_W