closed between 1911 and 1926?
The pub is shown on OS maps at least as late as 1905, but has gone by the 1926 sheet, so presumably it closed between 1911 (the last directory entry found) and 1926.
The current building on site is not the Plough, but a later replacement.
Historically, the Plough was in Assington, before Leavenheath was created in the 1950s, so will appear in old documents under that parish.