Changing bank accounts

Hi all,

I really want to change my bank account (had enough of Santander they were good as Alliance and Leicester) but I will be getting a mortgage of my own in the next few months (after coming off a joint one with my ex) so I wanted to know how much of an affect changing bank accounts will have on my application? Will it matter will I need to have had an account for a certain period first?

Cheers.