Hi Kazza and Welcome to the forum, you might want to have a look at the following FAQ which explain where everything is
Welcome to Benefits and Work You should treat the reassessment in the same way that you did the first claim. It is unlikely that the assessor will have any prior knowledge of you or your claim so you should complete the ESA50 form in detail and submit all the evidence you have.
Our ESA guide will explain how to describe your limitations, whether or not they vary from day to day.
ESA claims and appeals You might want to bookmark/favourite this on your web browser now so that you can find it easily in future. That will allow you to return with further questions/queries rather than having to start a new topic each time. It helps us enormously when everything relating to the same claim is kept in one place - and I hope you will find it useful too