The Courtenay model 151 was manufactured for Turnbull & Jones Ltd by Radio Corporation of New Zealand Ltd in 1939.

5-valve broadcast-band radio. 

Serial number above shows manufacture in 1939, however 1939 Courtenay models typically all had large aero dials, slide rule dials were not introduced until the 1940 season.  The ARTS&P label is also indicative of 1940.  The chassis is also very deep, similar to the model 94 and 95 from 1939.  And the triangular dial layout is the same as 1939 models.  Finally, it is extremely similar to the Columbus model 95 with rectangular dial

It is likely that the slide-rule dial was a production change from an original aero dial or it was simply a test implementation of this new dial design.  If anyone has an aero-dial version of this set please send information. 

This set is likely to be very similar electrically to the model 94

Valves (5):

Frequency Bands: 1

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.