Also add ClearCash and Secure Trust accounts as alternatives. They do carry monthly charges, but acceptance is guaranteed even with the worst credit rating.
...Don't have a Credit Union anywhere near me, but a good option if you do have a local one.
I can personally vouch for Secure Trust though.
Don't be put off by the Monthly £12.50 fee. This can be easily off-set by taking advantage of the automatic 3-7% cash-back applied, works with a lot of the big household retailers: Asda, Argos, Boots, Wilkinsons, BHS & Debenhams to name but a few.
Do your weekly shop at Asda? Job done. You can also allow for the Monthly charge in your allowances.
I understand ClearCash (and other similar card-based accounts from Cash Plus, Think Money etc.) also operate similar 'cash back' schemes as well.
My opinions are just that: Based on my experience and being a self-employed IVA customer.