Hi Gorge,
you need to ring them and ask for a mandatory reconsideration, ask them to send it to you via the post so you have proof you’ve asked for it.
When you send the form back to them, make sure you have it signed for as proof that they’ve received it.
With the form make sure you send anything that helps your appeal. Proof of illness, reports in the press on how they discriminate against mental health claimants, anything that you feel may help your case.
Don’t think that they will do anything to help you, you need to provide it all to them.
Both the assessing company (Capita etc) and the DWP will blame each other, so it’s hard to get at the truth.
Your mandatory reconsideration could take anything from a couple of months to a year! So make sure you send as much evidence with your returning of the form.
If you lose the appeal you can then as to go to tribunal, but that will take many months also.
The bottom line is send anything that proves your illness and how it affects your daily life.