Help After number migration, phone still uses old number

[TuskenRaidrBob]

I'm on Three and I got my old O2 number migrated across, but the phone still thinks it uses the number that it came with, noticed it when I installed Ping Chat, also in the phone's settings, the 'About phone' section it has the old number (Three one) as my current number and there doesn't seem to be an option to change it. Voice calls and texts come through on the correct number (the O2 one), is there a way to get the phone to accept the O2 number instead of the original Three number?

 

[snapper.fishes]

I think you can change it in Contacts. It's somewhere in menu.