Never heard of T Dale.
I don't think there were any "real" gunmakers here in NZ,or even anyone assembling them, though that may have happened in very small numbers.
The big players were A&W M'Carthys,W H Hazard,Tisdalls,and Colonial ammunition company(CAC), all retailers of guns and fishing tackle etc though Hazard did list as a gun maker.
Still very common to see these older, generally hammerguns around but they all tend to say "made for" the above by various commonly known Birmingham firms.

GDU.