Please help me.. Very urgent

[RGUK]

I came here in UK in 2010 under Tier 1 G and after one year my wife came as dependant. She only had her first name in the passport(Lets call it X). Lets take My first Name as A and last name as B.
When she got her dependant visa her name was X. Now we are thinking to change her name to X B by endoresment.
She has two bank acoounts and in One bank her name is taken as X X and in other its taken as X B which is joint account.
My extension is due next year. Should we proceed and change her name to X B or not?? She and me are having joint account(her name there is X B) which I'll show as bank statemnet and funds.
If not should I change her name from the account and make it X X or should I make that account single under my name.

Please help

[innocentdevil]

regardless of a bank accounts, name change shouldn't make any difference to visa application.