Factual error: With the exception of the RSM, no NCOs are ever seen. Stephen appears to have no platoon sergeant and no section NCOs (corporals or lance-corporals). There is no company sergeant-major (the RSM appears to do his job). There are no NCOs in the tunnelling company (which appears to consist only of a captain and half a dozen sappers). The entire army appears to pretty much consist of officers and privates with nobody in between.
Factual error: The battalion commander wears the correct crown and pip of a lieutenant-colonel, but the four cuff rings of a full colonel (lieutenant-colonels wore three).