My husband and I are thinking of buying a transportable granny flat and putting it in his folk’s back yard. The granny flat costs $108 000, but would we get the first home buyers grant of $21 000, even though its not an established “house”?

The grant is for the purchase of your first home which assumes it is on its own block of land or in the case of a unit it owns strata title to the space occupied by the unit plus a proportion of the common areas.
Additional information: I just read the other day, that the grant is available for caravans providing that they are fixed to the ground with water and electricity connected and with council permission to be permanently at that site.