I work for DWP and I feel terribly sorry for everybody that is claiming UC when it is completely out of their control as to whether they can work or not.
When filling out your claim form, if you are self-emoloyed, PLEASE say that you ARE going to be self-emoloyed in the next month (unless you have completely closed down your business via HMRC/Companies House).
By saying you are self-employed, you will be asked at the end of your assessment period how much you took home from self-employment. (Even if it's £0).
When you do your taxes, HMRC will know you claimed UC and you will need to pay none/some/all of it back depending on your self-employed earnings.
I've had too many customers declaring they're no longer self employed because they're unable to work. It's not as simple as this and I'm more than aware that the claim form doesn't explain this in more detail.
I know this isn't AIBU but if it helps one person, that's great.