[updated post] If you need a better copy of the image please ask. (as usual click for larger)
WMO03857, Isle of Portland
50 31 19N 02 27 20W
Altitude 52 metres
Need confirmation of Stevenson screen location.
Estimated Class 4. Given the unstable environment at the met station, which can be deduced from the few Google aerial images taken at different dates and also from photographs this site might be Class 5.
UHI, local possible severe including recently parked cars and caravan storage, distance, none.
Commenter Caz pointed out this site includes rented holiday cottages, in consequence I have been able to unearth photographs, two are referenced here.
- Less distinct aerial from the west, enlarge the left hand image, the Stevenson screen can be seen.
http://oldhigherlighthouse.com/ - From the east a more useful image, penultimate on the following page, also magnify
http://www.sykescottages.co.uk/cottage/DorsetSomerset/Old-Higher-Lighthouse-Stopes-Cottage-12494.html#
From these I have pieced together the situation as it applies to the circa 2005 Google image. Since then the grass cover has vanished from the east side of the enclosure and worn further to the west.
Portland is essentially limestone, literally Portland stone came from here.
Tallbloke's Talkshop 
Very difficult to get any info on this one. Everyone is interested in taking photographs of the three lighthouses and look out station and have ignored the weather station. But you have correctly identified the location of the station as this video confirms at 34secs in, unfortunately photographer deciided to start zooming out just before this point and the only thing that is really obvious is the ten metre wind mast. This is further confirmed by the shadow of the mast in both Bing and google and is located in the south East corner of the station. So you have a choice of two boxes for the location of the screen. The old lighthouse is actually holiday cottages so it may be worth emailing or phoning them.
Got it. Trying to figure what to show.
Major post update.
Well done Tim especially on your reference 1. I even phoned the look out station about this one and I won’t embarrass them by saying where they believed this station to be. And they are sat right next to it.