You can, in fact, represent yourself in the higher courts, without recourse to a lawyer. Unfortunately, you will be playing on their terms, and it is unlikely anyone will tell you what the rules are. For this reason alone you need a guide of some sort because otherwise you will immediately put yourself at a disadvantage.
I agree that the Small Claims Procedure is a good system in that it obviates the need for lawyers. However, when the stakes are higher, it may be prudent to employ help, on the basis that lawyers carry indemnity insurance in the case of professional negligence.