Confetti clearly draws its inspiration from all the best british mockumentaries on TV (namely Ricky Gervais' The Office and specially Julia Davis and Rob Brydon's Human Remains), but unfortunately it lacks the bite that makes those - and also the Christopher Guest movies, like Waiting for Guffman, A Mighty Wind or The Best in Show - really funny and tragicomic slices of life. Confetti ends up being a bit shallow, a kind of Human Remains for the family entertainment crowd... The only time it tries to "shock" is by showing Olivia Colman and Robert Webb full frontally naked - and that gag eventually runs out of steam.
That said, the natural lack of bite that Debbie Isitt (the director) seems to have for this noble comedy genre is compensated by all the amazing actors she managed to gather for the film. It's an amazing who's who of the best modern british comedy, some of them with experience in the genre - like the amazing Martin Freeman, Felicity Montagu and Julia Davis - all of them at the top of their game. Confetti has very funny moments because of them, although, by the end, it's impossible not to think that this could have been a masterpiece.
It's not, but if you're a fan of the actors, it's still worth seeing.