GeoGraph - photograph every grid square

I have to confess to being less than 100% certain about the identification of this building in Elfrida Street. Watford Borough Council's Listed Building file shows "The former St James Church, Lammas Road, built 1890s, tall nave with aisles, overburnt brickwork with yellow brick details, consecrated 1913, later additions (eg chancel in 1928)". Lammas Road is at the end of Elfrida Street here, but the Ordnance Survey 6" to 1 mile mapping editions of both 1899 and 1920 show this as a vacant plot of land. Only in the 1938 edition is the building shown. The cross on the cupola is evidence of its ecclesiastical origin, and I also think it is now in use as the church annexe of the adjacent Field Junior School. I can find no other possible references to a St James Church currently on the internet.