Could this be him here? inmelody - music teachers

If you click on 'string', the second one down says:

"David Coulter (Guitar)
Guitarist David Coulter has a long history in folk music, playing mandolin, banjo, cittern, autoharp, concertina, and so on, as well as guitar. He is a music teaching graduate from Sydney University." and there's a photo.

They are at Hurstville, which is not all that far away from the suburbs you mentioned. Not all that far away from me at Earlwood, actually. If you click on 'contact' there's a phone number too.

I'm wondering though if the website is up to date. Where are you, Commander Crabbe? If you aren't local, I could ring them for you and find out if he's still there.