There was in fact never a campaign to stop the Half Moon becoming a gastro pub, but why let the truth get in the way of a good story. There was a campaign to stop thye pub being sold to Grand Union who had intended to discontinue the live music for which the pub is so famous. Following that reprive, the pub was taken over by Geronimo Inns, a gastro pub company, who also own a couple of live performance venues. They invested heavily in the pub, especially in revamping the main bar, adding a dining area, and spent thousands on the music venue. And yes, the pub would now be considered in the gastro pub bracket, and it continues to be the best little live music venue in London. Since Geronimo's take over the pub has sold more gig tickets than ever and also sold more food than ever. Long live the gastro pub.
Also, the picture above is not of the Half Moon. They would never serve anything but Guinness in a Guinness glass.