I'm getting a daily call from a variety of area code 02-numbers, with no voice message.  

Same here on a daily basis! So freaking annoying! I've only had this mobile number for 2 months....last one I had for 15 years and had no nuisance calls.I've called them all back to see where they go and nothing. The nunber that they rang on today went to a voice message, saying that it was a call from ways phones (checked their website and they are people that do calls for carities or something like that)