Cherub was a brand used by Arthur Foister Ltd, later Arthur Foister & Sons Ltd. I searched the 1921 census for people living in Leicester with name of employer = Foister and got 280 results. Looking at the first 10 of these I counted–
5/10 were some variant of Arthur Foister & Sons, James Street [the firm moved to Charles Street later]
4/10 were some variant of M C Foister, High Cross St. [Arthur Foister’s brother, a separate firm]
1/10 W Foister, tanner, Friday Street.
So, based on this rather small sample, about half of the hits are Arthur Foister-related, thus there were VERY APPROXIMATELY 140 employees of Arthur Foister Ltd. in 1921