Thanks both. There are no Plans of Division in the extra materials for this particular record set. The cover image indicates that the piece covers part of Romford South Ward. The Romford Workhouse is shown on the maps to the SW of the town, but the workhouses.org.uk site states that Romford Union used the scattered homes system for children from 1905, and there appear to have been homes in between five and eight locations in Romford and Ilford by 1914.
I already have a page from a different piece in the 1921 census for this individual's older sister, at a scattered home in King Edward Road, Romford, also in the South Ward, so at least I know it isn't that one.
I will have to do more digging and see what comes up. I haven't been able to locate a reference for piece numbers so far.