I'm currently staying in Holland and my phone refuses to connect to any of the available networks it finds after a search. What is the service it should be connecting to for the Netherlands?

It may depend on who your contract is with in the UK. You might need to contact your service provider.

According to the Virgin website, you can roam on pretty much any of the networks for voice and texts. Vodafone NL seems best for data.

Visit the Virgin Mobile website and click on Your Account just to see if roaming has been switched on.