Thank you for the advice, it sounds very assertive, I would like you in my corner during a row!
I am a bit nervous about this, mostly because it is my fault and my feel like I am begging and will cave in because I'm in the wrong. When I fill out the form do I just send to Wonga with a cover letter as you suggested and just keep everything in writing? I assume also that I have a word with my bank about the continuous payments. Although my bank are quite funny about Wonga payments, in the past when I've paid a rather large lump sum, they stop the payment and my card and someone at the bank said it always gets flagged up because not many people can pay off a Wonga loan outright! I also don't keep large amounts of cash in that particular account so they wont be able to get at anything.