P.s. don't send them that email you've posted above. It's pretty poor and reinforces to them your nature of being a walk over.
Oh
I did send it but thankfully I received a voicemail earlier confirming that they are going to give me a refund They'd discussed where they stood with trading standards and apparently received mixed messages from them. Whatever was said though, the result appears to be a positive one.
At least it will be once I actually see the money in my account.