It's a hit-and-miss confection overall, frothy and fun, oblingingly offering up most of the most famous bits of the movie (although the appearance of Tim the Enchanter seemed unnecessary, given that he asked no questions). There is shrubbery and limbs chopped off and people who are mostly dead (but have to sing one of the show's weakest songs). There are also new elements, most notably the addition of the Lady of the Lake, since otherwise there was no major female part. She was wonderfully over-acted, and given fabulously self-parodying numbers to sing - but the part itself was minimal, and the role has less personality than the others. I was particularly won by the actors playing Robin and Patsy. Lancelot should have been an overdone role, but was merely done.
There was no Brian, but there was "Always Look on the Bright Side of Life", which was better integrated than I'd feared. There was an excellent weather forecast, and a cheery Finnish fish-slapping song, and disco. There were cheerleaders and lots of knights getting limbs chopped off. Overall, the musical parodied - or at least referenced - at least a dozen other musicals. Yet the whole thing could have been even better if the writers had realized from the start what their strengths were - the token plot was better staying token.
Thanks to haggisthesecond and naxos for organizing.