About adding extra sheets to anything sent to the DWP (or any other bit of state bureaucracy). I always number not just page 1, page 2...page 5, but page 1 of 5, page 2 of 5 etc. That way if they lose a page, they know they have.
Go to the left hand side of the screen and click on Help for claimants. Click on Incapacity Benefit. Pick the guide to the best claims for IB that is appropriate (mental or physical grounds) and you'll find help in there.