My son as broken his Lg U400 that is on a Three £15 675 contract and is not insured 
I have taken his Sim and put it into an old K800i 02 contract phone that as been upgraded
As the 02 don't lock their contract phones , or do they ?
It works perfectly
Two questions , will Three or 02 know or care which sim is been used in which phone
And as its an 02 it doesn't have the planet 3 dedicated button to check his balances , is it possible to allocate a key to connect to Planet 3 or any easy way to check balance by dialling a certain number or even dedicating a key to accept this shortcut
It is registered at "My Three" so his balance can be checked online if need be , but he wanted a simpler method without the need for computer access
Thanks

I have taken his Sim and put it into an old K800i 02 contract phone that as been upgraded
As the 02 don't lock their contract phones , or do they ?
It works perfectly
Two questions , will Three or 02 know or care which sim is been used in which phone
And as its an 02 it doesn't have the planet 3 dedicated button to check his balances , is it possible to allocate a key to connect to Planet 3 or any easy way to check balance by dialling a certain number or even dedicating a key to accept this shortcut
It is registered at "My Three" so his balance can be checked online if need be , but he wanted a simpler method without the need for computer access
Thanks