I thought I'd check out the "Action for Renewables" website, and found something interesting. This Green campaigning organisation is actually run by the British wind industry trade body RenewablesUK (formerly known as the British Wind Energy Association or BWEA, but it now covers wind and wave power):
"About Action for Renewables
Action for Renewables is an arms-length campaign of RenewableUK (formerly BWEA), the trade association for renewable energy suppliers in Britain. While it is sponsored by companies, the campaign itself is activist-led - The website provides the facilities for renewable energy supporters to campaign directly to their elected representatives, as well as organise campaigning events for themselves."
So RenewablesUK appears to have set up its own Green NGO rather than relying on the likes of Greenpeace. It might be that the established Green NGOs are cooling off to some extent in their promotion of wind energy, or are not seen as doing a good enough job in protecting the wind industry's flow of subsidy money.
Jonathan Pyke doesn't appear to be one of the activists, he is actually employed directly by RenewablesUK as the campaign co-ordinator. He is listed as one of RenewableUK's staff on this webpage:
For anybody who has heard the expression "All chiefs, no Indians" to describe a company, I'd say RenewablesUK represents a pretty good example. It looks like about two thirds of the staff are directors, managers or heads of something or another.
I originally assumed the claim that wind is providing back-up to fossil fuel was just some blather by a Green activist. But as Pyke works for RenewablesUK, this claim might be more serious than I thought.