A circular structure measuring some 7.9m in diameter is shown on aerial photographs dating to May 1946 (thin white circle enclosing a dark area). The structure is within the enclosure containing a large hanger (formerly glasshouse) (see NPRN 506296). Two other such features are visible on the same aerial photographs (see NPRNs 506515 and 506744) and are believed to emergency water tanks.

Sources include:
RCAHMW aerial photohraphic collections, 106G UK-1450-4147

Maritime Officer, RCAHMW, January 2010