The following text is from the original listed building designation:
HILDENBOROUGH MILL LANE (east side) TQ 54 NE 5/160 Remains of windmill in the garden of the Old Mill House 20.10.54 GV II
Remains of a windmill. 1812 (Old list description) struck by lightning in the 1960s and now a brick shell about 5.5m high. English bond handmade brick with some blue headers.
Plan: An octagonal roofless structure.
Exterior: The remains of a segmental arched doorway on one side, 2 loft doorways and 3 unglazed windows, all with segmental arched heads.
The 1952 list description described the upper parts as weatherboarded with a revolving pivoted head, intact sail arms and the remains of a wooden platform around the base. The mill was in working order until the 1960s.
West, Jenny. The Windmills of Kent (f.p. 1973, 1979 edn.).
Listing NGR: TQ5596449654 (1)

A smock mill for the milling of cereals, built in 1812. The mill was in working order up until the 1960's when it was struck by lightning, even though it ceased work in 1910. The mill is now only a brick shell, but it originally had a weatherboarded top (2)

Historic England archive material: AA78/01209 Bags of cereal being loaded onto a cart from Watts Cross smock mill Watts Cross smock mill was built in 1812 for milling cereals. It ceased working in 1910, but retained its machinery and was in working order. However, in the 1960s it was struck by lightning and now only the brick base remains.
BF002514 WATTS CROSS WINDMILL, HILDENBOROUGH File of material relating to a site or building. This material has not yet been fully catalogued. Copyright, date, and quantity information for this record may be incomplete or inaccurate.

<1> English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.

<2> A A Bryan, 1998, Windmill gazetteer for England (Monograph). SKE55552.