Well this is after curtailment. It's power in the grid.
...but yes there is a problem getting the power from the farms (mainly Scottish ones) to where it could offset gas turbine generators (mainly the south). So they have to turn turbines off.
Newer farms are tending to be built in more varied locations making it less of a concentrated problem, but it's a real thing and why there's been lots of talk of needing new pylons.
...because you're on a price plan that doesn't get cheaper on windy days.