This is what you should put in your Die Tidy, and why:

Item Reason to include
Will Include your will if you have one, or include a note saying where it can be found. If you don't have a will, or if it can't be found, the rules of intestacy will govern the distribution of your assets. This may not match your wishes.
Expression of Wishes An expression of wishes is not legally binding, but can guide people in things like: who to inform of your death, funeral arrangements, whether you want a religious or non-religious service, whether you wish your body to be buried or cremated.
Certificates Include your birth certificate, marriage certificate, certificate of divorce (decree absolute), and other similar certificates. The information from these maybe needed for the various forms that will be completed after you die (such as for the death certificate and inheritance tax forms).
Driving Licence and Passport These will need to be returned to the issuing authority for cancellation.
Vehicle Registration When you die, any vehicles you own will become unregistered. These will need to be registered to another keeper - probably your personal representative until the vehicles are sold for transferred to beneficiaries.
Annual Review This will give your personal representative a head-start in valuing your estate for probate.
List of Assets and Liabilities Your personal representative will need to contact all the organisations with you have assets (credit accounts) and liabilities (loans, credit cards). You will need to provide a list of these with the respective account numbers.