OK, so not quite a castle
but an interesting building nonetheless.
A quick cache'n'dash accessible to all.

Built in 1900
the water tower was constructed in the Tudor style, with a turret,
slit windows and battlements. It is a striking orangey red colour,
and was built from locally manufactured bricks.
On 23rd August 1941, 8th August 1942 and 22nd January 1943 bombing
raids were carried out upon New Milton by the German Luftwaffe. The
town's water tower was suggested as the target.