The website has 2 pdfs on call bands and charges.
From what I could work out calling 0300 is chargeband N3.
Can't find it in the calling costs pdf though, nearest I can find is PN3 which is 7p connection charge and 7p per minute.
http://allyours.virginmedia.com/html...lingcosts.html
HTH
If I'm wrong, someone will be along to correct me and give you the correct info.