It took me several months, with the help of another climate scientist, to find out why Myles Allen thought that Gregory et al "implicitly use a uniform prior on transient climate response" and then ultimately to persuade him, and thus Gabi Hegerl, that this statement also was incorrect - and that I had been right all along in saying that in fact this study implicitly used a nearly uniform prior in the climate feedback parameter.
Gabi and Myles were not keen to get the IPCC to issue a further Erratum, which would obviously be embarrassing, so I agreed not to pursue the matter further.
Wouldn't want any embarrassment. Not will hundreds of billions of dollars at stake.
Edit -- This was a comment by Nic Lewis in a thread on this post. Errors on top of more errors in key areas of the global warming argument. Climate sensitivity is absolutely crucial to the argument. That the studies relied upon are so poorly done speaks volumes about the sloppiness of the alarmist cast. But it shouldn't be surprising. Sloppy seems to be the standard.