Thanks for those comments. I've now done some research. Yes, a RCA CDP1802 device possibly based on the ELF-range of computers.
As one person mentioned in another forum I posted this message to, 1984 is a bit late for a 1802 trainer. It's also a bit late for a "build-you-own-computer" kit when you could easily buy a C64 off the shelf. I'm puzzled as to what if would have been made and sold for. What was the purpose. Perhaps it was used to control something else, although the homemade case would suggest something of a hobbiest nature. The only thing that hints at a manufacture is “Lang 1984” and the small word “Commander” at the very bottom in the centre. I don’t know if it was made here in NZ or elsewhere? Tantalising lables like "BURNROM", READROM and RUNROM would suggest it could (or had) some role in play in burning EPROMS?
@ZL2AOX - Thanks, but I'll keep it for now. It may not be classic but it's certainly a curiosity.
I notice 1802 chips are available on e-bay for collectors that want one (see ebay item 330550857955)
#welshwizard - If there was relevant info in that link you posted, I couldn't seem to find it?