Hi AndrewPatrick
Have a look at the Guide to PIP claims and reviews. The review information is from page 129 onwards
benefitsandwork.co.uk/guides-for-claimants/pip You can attach any number of additional sheets that you need to.
I don't know whether you have an AR1 or an AR2 form - but don't fall into the trap of ticking 'no change' and not giving any details. Even if your condition is unchanged, describe what hasn't changed in a few sentences.
BIS