As you're now on Talk Unlimited you don't want to be calling any 08** numbers if you can help it as these non-geographic numbers are still chargable (except for 0800 of course).Have a look at "Say no to 0870"
http://www.saynoto0870.com/search.php
where you can find alternative 01/02 numbers for nearly all banks, utility companies etc. Often you'll get through to a switch board but you just ask for the department you want. Sometimes even gets you straight through without you having to go through the menu.
Sparky621