WMO03710, Liscombe
51 05 13N 03 36 32W
Altitude 348 metres
Estimated class — discuss.
I have known of this site for several years and that it is unusual in being surrounded by a hedge. In the context of trying to classify according to WMO 2010 this raises a question of interpretation. See continuation below.
UHI, none.
WMO 2010 make no reference to a meteorological site enclosure or fence yet these are common for security or site integrity reasons: such as keeping sheep or tractors away from the instrument.
For Class 1 and 2 it states
“Flat, horizontal land, surrounded by an open space, slope less than 1/3 (19°);”
and
“Flat, horizontal land, surrounded by an open space, slope inclination less than 1/3 (19°);”
Class 3 and above omit this requirement.
In the case of Liscombe the hedge at 10 metres could be taken as a wall, Class 3 or does not exist, Class 1.
Any opinions or ideas?
Tallbloke's Talkshop 
Yes the northern boundary can be taken as a wall. The weather station has been placed inside a field next to a farm lane. As is common on the South West peninsula that hedge is in fact a stone wall originally bonded by earth with turf on top and over time plant life takes over and makes these stone walls appear like earth banks or indeed natural hedges.
Don’t know about the other three sides though. These days as it is inside a national park the planners would probably insist they were made out of local wallls but I think they may be livestock fencing then planted out with bushes. The East side is pretty none existent anyway and relies on the original field wall/hedge which appears to be planted out with trees along its length. Given the location of the site the wind will make sure these trees do not grow tall
The Lane a few hundred yards west. As you will notice on google mapping the northern wall to the lane ends at the Western boundary of the weather station.
As near as you can get on Google street view
http://goo.gl/maps/SdiBQ
There is plenty to discuss about the meaning and intent of the WMO doc.