Hi. Your concertina is a Lachenal Anglo model. The diagram next to the word English was their trade mark, it is a depiction of the reeds used to sound the notes. As an Anglo with three rows, it is more versatile. The age could be achieved approximately if you could read the number clearly.
Bone buttons were quite usual, guessing a price without visual inspection, inside and out, is not really possible.
Though hopefully some Australian player, there are quite a few, may be able to help you further.
Tutor books for the Anglo are readily available, and Youtube has many postings.
Hope you have a good adventure with it.
Good to have discovered your name on this forum. You may remember me (Graham Else) from Aylsham SA days in the 1960s.
You inspired me as a young man to take up the concertina and I've now been playing anglo for 40 years.
Would be great to meet up and catch up sometime.
Cheers for now