'Gift In Your Will' Leaflet

Hi, I have just started as Fundraising Manager at Age Uk Milton Keynes and have taken on responsibility for legacy marketing. This is a news field for me and as a starter I am organising a legacy event at one of our venues which we are invitinf solicitors, funeral directors and supporters to. We have virtually no marketing materials at present so what I am thinking of doing is creating a DL gatefold leaflet on why the supporter should leave a legacy to Age UK Milton Keynes. Can you tell me what essential information should be included in this leaflet? Thanks! fom Chris