Swapped to a co-op cashminder account for the duration of my IVA and had no problems at all but I did manage the account responsibly so no idea what they are like if you mismanage your account.
Still bank with the co-op now.
Surprised you were able to get a savers account - Co-op aren't known for giving them out.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
I read somewhere about Monzo, I quite like them myself, but I only use my account with them as a secondary account to my co-op account, somewhere I can stash those allowances I need to save and little extras like the council tax I haven't paid on Feb / Mar and my share of any overtime.