Good spot Rob! But the census number looks genuine to me (typical BSA font and style). So I also had a look at the Chilwell list. And here I found something weird: census numbers 4364197 - 4364446 had a C prefix according to the original Chilwell list (although they are listed against a Crane contract). Rob must have amended this C prefix with an X prefix.
So there's definitely something wrong here. Now could it be that this is a (small, 250 bikes) BSA contract after all? And that it was mistakenly entered as a Crane contract...? 🧐
The census numbers block C4361416 - 4364196 (which is the block just before this mystery block) was for contract C8136, a Royal Enfield WD/C contract. Demand date 24/07/40, contract date 25/09/40, de"liveries from 05/06/41 to 21/10/41. Is there a missing BSA contract for 250 bikes around that period I wonder?