Why do all my incoming calls have a number 7 preceeding them

[Guest DrG]

All my mobile numbers are stored as international format i.e +44xxxx and all my other nubers are stored as the normal city codes etc. So why do they appear with the number 7 infront of them when i am recieving a call? This dosent help with assigning a custom ring tone to the number as it doesnt regognise the numberas of the 7 infront but it does know whose calling from the contact list (wierd)!?

please help.....