Welcome to the Leyland restorers 'club'. Lots of early Leylands in Australia and New Zealand. Fertile ground for these beasts.
Most are a mix of two/four/six ton being S3 variants, and larger PH2 & 4, also A type. Several later fire engines reside in NZ - Ferrymead. No SQ variants; that I know of.
A very few pre-great-war Leylands exist. A 'U type' fire engine in Hobart. An X4.40.V, and a very early S(?) in NZ. And, what I believe to be an S2, in my shed.
Cheers
Robert