You can, of course, update your own trust deed with a Deed of Variation if you know what you're doing or you can get the wording from a reasonable source if you don't. Most changes required are to keep the deed in line with current legislation. Any auditor should highlight the area that needs amending/adding - you are paying a lot for annual audits, so get some value out of them!
The Trust Deed is YOUR document and doesn't need an expensive lawyer to do a 2 minute cut and paste and charge you a monza for the privilege.
Of course, if you are not confident doing it, just pay the money and get a professional. About $500 is typical, though you can shop around and half that cost.
