7-valve + eye broadcast-band radio or radiogram, magic eye tuning.
There is a model 809S, with a different circuit - a stereogram. This model, the 809, is mono.
Similar to the 810, although the 809 does not have short-wave reception.
Chassis Notes (most schematics can be clicked to download a full size version):
The valve lineup is believed to be right - the circuit is not held, but is probably very similar to the Columbus 810 without the shortwave band.
General Construction Notes for Radio Corporation of New Zealand Ltd: The first digit of the serial number typically indicates the year of manufacture of RCNZ chassis' (although not the decade - that requires a little knowledge of the valves, construction, etc). Sets from around 1934 onwards were often (but not always) constructed in a distinctive pressed 'baking pan' style chassis, seemingly unique to RCNZ.