My half-decker was Ala, designed and built by Cyril Richards and Ivan Darby, but also helmed by Jimmy Clabburn, an Olympic helmsman in Stars and superstar skipper in any Broadland sailing yacht.
Here's a link to a report on how Ala sailed away without me! It includes some historical detail.
Ala had a larger sail area and, apparently, one side of the bow was fuller than the other so that the boat would perform better on the most common beats sailed on courses around Oulton Broad. I don't understand all the technicalities, but it seems that it has something to do with the prevailing winds during the racing season.
The main builder of Ala was Harry Francis who was in his 70s. But I was told the story, of how she was built in secrecy at Cyril's shipyard, by a man who had been an apprentice to Harry.
I've no idea where Ala is today.