[David_Hayward (RIP)]

APJ, that makes sense thanks! These CKD crates were mixed up, and the Engine Number mixes seem to prove that this was the 'case' if you'll excuse the pun.

The 'XH' code obviously indicates General Motors New Zealand Ltd, founded Petone in October 1926. The only other plant to allocated an 'X' code so far as I know was GM South African Pty Ltd in Port Elizabeth, code 'XG'. GM-Holden's generally just used the city code for each assembly plant, and did not use an 'H', e.g. 'HA' for Adelaide until the 1950s I think when the 'X' codes were abolished in favour of codes abbreviated from the city or company, e.g. 'NZ' for Upper Hutt, NZ, 'SA' for South Africa, and for our Dutch friends, 'C' or 'CA' for GM Continental, Antwerp.