Moving mortgage from "one" account

Just a quickie,

Anyone had any experience of moving from a mortgage like "virgin one"?

Im moving to a fixed rate with another lender, and am wondering how it will work.

Normally you could keep an old bank account open "just incase" the direct debit didnt change in time, but with a current account thats basically a flexible mortgage - how will that work once its been paid off?

Is the account totaloly closed, or does it stay open as a current account?

Does this make sense?

Hope so :-)

Thanks