It is all there on the site you linked to. There is a download option and you can select which items and which time period to include.
As well as the Gridwatch site, there is the
BM Reports site as part of NETA (New Electricity Trading Arrangement) - I believe it's where Gridwatch gets it's data from. it used to have some nice pretty graphs, but they went when they did the "new improved" site.
Also, one of the tables they had included the metered capacity which made it easy to work out % of rating plate capacity actually being produced. For renewables, there are a lot of smaller sites that aren't metered (their output only appears as a reduction in total demand) - and I don't think there are any figures for how much capacity they add up to.
I am not aware of anyone 'sneering' at so-called renewables because they don't (or can't) work but because they are not economic.
Not only are they more expensive than reliable electricity supplies but their variable supply makes them worth less than reliable supplies. In a free market I don't think that any electricity company would buy wind derived electricity at any price.
It's the latter that I have an issue with - and the costs to the rest of the industry (not to mention the £11,500,000,000 project to foist smart meters on us).
Fair enough. It's far from any of my areas of expertise, but I would have feared that if one simply 'applied a brake' to the blades (without altering the angle of attack), whilst one would obviously eliminate any over-speed problems, the stresses on the structure could be pretty large - the blades are, after all, trying hard to rotate rapidly.
Well they certainly stop the turbine when the wind is too strong - otherwise something would break, either overloading the mechanics and generator trying to control the speed, or simply flying apart when the speed got too high.
I don't know how other turbines do it - I suspect smaller ones just use the brake, but on larger ones that could be a lot of power to dissipate.
So I did a search, and came across a few links.
First,
a video of a turbine being stopped by fully feathering the blades. Once fully feathered, there's a lot of sail to drag through the air - so highly effective. Also, there's less twist in the blade profile than I thought.
Fluid dynamic model of a turbine doing such a stop.
What happens
when it goes wrong 
What they do with aircraft engines to stop the bits going through the passengers -
A380 blade off test, or how to destroy a £9m engine in five minutes
A summary of the methods in use according to the Danish Wind Industry Association.
Seems I'm a little out of date, but then I've not been following the area that closely.
And for a bit of fun, a compilation of
Dyno run fails 
