I was out with the telephoto lens yesterday with the purpose of photographing Chanctonbury Ring (a tree circle landmark on the South Downs in Sussex) from a footpath in my village. The village lies on a greensand ridge, and there are wonderful views across the Adur valley to the ridge of the downs.

I was snapping away with my camera on a monopod, to steady it at the 250th shutter speed, when I spotted what looked like a white-capped tower below the Ring, to the north and west of it. Was it a dovecot? Could it be a windmill without sails. I dismissed the windmill theory, having been a devotee of Sussex windmills for many years. So I noted the position of the white cap as part of a triangle - me; the Ring; the tower, and walked home.

I'm a Premium subscriber to the British Ordnance Survey online map service so, when I got home, I opened up the laptop and the OS application. I zoomed in to my area and drew a mental triangle on the map on the screen. The only sign of habitation in that area was the village of Washington (Sussex). I zoomed even closer and there, just to the east of the village, was the legend "Rock Windmill".

So much for my 40-year old knowledge of Sussex windmills - I thought I'd seen and photographed every one in the country. A Google search revealed it to be a converted mill - hence the lack of sweeps - now in use as offices.

Many thanks to the Ordnance Survey for their precise and full mapping. If you're interested in Rock Mill, look here:

Rock Windmill