Improvements by prospective tenant and relation to AST agreement.

Tenancy Types and Management

I have a flat to let that has an older kitchen bathroom and heating system which are all clean functional and safe. I have had a prespective tenant ask if I will reduce the rent further and he will instal a new heating system, kitchen and bathroom. He has idnetified that he is disabled so will get a grant for the heating,because of the investment he will make he also requests an agreement for 2 to 3 years.

If someone has a disability are they likely to get additional grants for a new bathroom or kitchen installation?

Do you have any advice on special requirements I should have in the AST such as:-
A break clause,
Written agreement of what will be done by a given time etc.
Insurance for damage, quality of work, approval of specific installations.etc.
Higher than normal deposit?

Additionally the prospective tenant, currently working for Barclays, is likely to be made redundant in the near future, and as such he has said he can not guarantee a employers income but he will have a large redundancey package that willl pay for the rent.

Do have any views on my requesting advance payment of the first years rent?