A topic which has been done to death, but student @Lakeside has come up with a short and sufficiently general definition that to me it covers recognised categories of self-builder.
Within my research I have created a definition of a self builder which is as follows:
1. they have acquired the land.
2. the risk ultimately lies with the owner.
3. the self-builder is going to live in the property.
It is quoted from this thread.
(* What does the piccie of 2 cats shooting a cannon have to do with the topic. Nothing. Explosive debate?)