Evidence of previous leisure activities that you are no longer able to take part in will be helpful for descriptor 15(e), provided your inability to carry out such activities are a result of mental disability, as opposed to physical.
Apologies for suggesting that you read the ESA guide when this is an IB appeal, but there is also plenty of literature for IB claims and appeals.
As Gordon said, if you can get face-to-face advice with your appeal, this would make things much easier as they will be able to look at the full documentation.
