02/02/1941 Pillbox shown on map - Knobbly No. 1. 11/02/2004 Brick-shuttered Dover-type square pillbox with overhanging roof slab. Faces across road beneath (N). Access possible. 13/09/1945 Large, square pillbox plotted from air photograph. 06/05/1942 Square pillbox plotted from air photograph.
01/06/1941 Pillbox plotted from German map. 1972 Square pillbox plotted from OS 1: 2500 sheet. 27/11/1940 Pillbox (Sector 5). Cassini ref 733581 Standard brick construction square pillbox with concrete roof slab 17ft by 17ft. (Survey details and discussion of type). (1) 01/06/1941 Pillbox plotted from German map.