Hi immi472,
Sorry for not getting back to you so soon, I havent ever had a problem with Virgin network as i believe its piggybacked on the t-mobile network which is really good. I know a fair few people with Virgin phones aswell as sim deals, as they do good deals on phones and sims. I tend to stick to their sim only deals as you only have a 30 day contract, as i hate being tied into lengthy 12-18 month contracts.