From late 1939 until early 1942 the RASC and RAOC each used their own census number sequence. Your example C1034001 is RASC, and C4191560 is RAOC. From approximately C4600000 onwards both services shared the same sequence.

Hi Roger, during the late 1930's and the early 1940's the census numbers were applied in the Army depots. From approximately 1941 - 1942 onwards this was done at the factories, who charged an extra cost for this service. Each factory had its own "style". See some examples below.

https://i.ibb.co ...

Five years ago I’ve made a CAD drawing of the typical Royal Enfield style census numbers, so that Axholme could produce them as low tack stencils. (https://hmvf.co.uk/topic/41549-royal-enfield-census-numbers-low-tack-stencils-now-available-from-axholmesigns/). Since then I’ve seen many Royal ...