A change of bank account is recommended if your current bank is a creditor ( or in the same group as a creditor). The reason for this is twofold: 1) They might grab funds from your account before the IVA is put in place to offset your debt to them. And 2) They might close the account anyway, without warning.
There are also a couple of banks that are IVA unfriendly and have a habit of closing accounts, without notice, whether you are in debt to them or not, namely HSBC and First Direct.
Finally, even with a friendly, non-creditor bank, any account will be reduced to a basic, no frills and no overdraft, account.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk