I've been getting calls from same number for past 2 days. Haven't managed to speak to the person on the other end as I've either missed call or I've been in a poor service area. It's about 4 calls a day. It's apparently a virgin number according to
http://www.magsys.co.uk/telecom/codelook.asp though I've no idea if that link is reliable, I just came across it when I googled the number.