Anyone got a reasonably accurate foreast for the inlands??

try this link. pretty accurate by far. dont look at the bbc weather FC as it changes by the minute!

Cloudy Saturday wind from SW 12-18 knots
Sunny Sunday wind ditto.
14-18 degrees high sun burn factor on Sunday.

Lots of wind sheer along the edge of the escarpment. 
Will twitch to the South at the Southern side od reservoir.

For SW read NW ignore wind sheer expect big shifts.

Or try windguru.

This one looks a bit more realistic, at least with the temperatures.

Richard, your selected spot is off Belguim
The link below is for the nearest I could find, Weston-Super-Mare

Wind Sat 12:00 8-12 Knots ENE backing NE 100% cloud
     Sun 12-13 Knots ENE backing 94% clearing to 84% Cloud

this is the costal forcast, drop the wind speed by 3-5 Knots or more for the lake.

Oops - didn't check the map location of the spot but Windguru does warn users that custom spots are unofficial and they're not responsible for their correctness - the user here either didn't check their coordinates or they're playing games.

This custom spot is for Cheddar Reservoir so should be pretty accurate.