The start is a little shaky as the actors and audience get to grips with the accents; Lyden and Phillips also had the added pressure of having to sound elderly as well. Once the actors get into their stride though, they're a lot clearer. Some have excellent enunciation; Tara Caple for example, playing Elaine- Mortimer's fiancee. Her breathy old-style Hollywood accent worked brilliantly for the role. The accents are consistent and whether accurate or not, at least they are clearly from the same state.
I'm not normally a fan of this type of play; I hated Deathtrap. I also committed the sin of hating a Hitchcock classic; Dial M For Murder (not a comedy but the similar sort of style). However it has the universal appeal of old people, who are inherently funny. I did cringe at the jokes about the theatre and being a critic- why does every main character in a play have to be a writer and constantly talk about writing?- but that's only a little creak in what is actually a very funny play. Machin's cartoonish facial expressions are funnier than some of the lines and Tiago Luzio makes delusional brother Teddy, who believes himself to be Roosevelt, hilarious and bombastic but also endearing.
The play is well-paced, with each act gaining momentum. It's the introduction of Elliot Huxtable as Jonathan Brewster, the black sheep of the family, that really gets the gears moving. His brand of lunacy is narcissistic sadism; botched plastic surgery has unfortunately made him look like Boris Karloff. Huxtable has the Alan Rickman-ish charm nailed, making his character devilishly intriguing. Joel Bates is a great sidekick as Dr Einstein (no, not THAT one), the shoddy plastic surgeon/accomplice.
Director Keiren Barton has a flair for this type of farcical drawing-room comedy, as well as an obvious affection for it. There's nothing worse than a director reviving an old play only to kill it off. It's the affection that he's shown for the material and the enthusiasm that he's conveyed to the cast that make the play a great bit of entertainment.