Hi MummyBear
As you informed them that you had a new diagnosis and told them additional information about your health conditions - this is being viewed as a change of circumstances, which is why you were sent a review form. They will then decide what type of assessment you will have, which could be paper-based, telephone, video or face-to-face. (Video and face-to-face are rarely used at the moment). So I can't tell you whether they will do a paper-based assessment or whether they may want to speak to you.
I know you have been waiting four weeks to hear, but the time you have to wait can vary considerably from weeks to months. Hopefully, you will hear soon.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems