Post Production
From 4docs
You can go two ways with post production
1) don't go any beyond what your home software (or your friends home software) will allow. This is totally fine for web shorts.
2) get professional post production either by blagging it or by getting a great cheap deal.
Professional post production
There are loads of post production houses in Soho, Manchester, Leeds, Brighton and other major centres - wherever there are TV production companies. Their rate cards will display terrifyingly high prices. The good news is a) that your short is not as long as a feature and so needs less hours work and b) that most post-houses like working on good short films as part of their job to reach out to future clients.
Whatever you do, don't pay the advertised rates. Go for free in exchange for a credit or cheap.
Which post house?
Televisual have a searchable database on their site with 267 post houses all over the country. You can search by region or by service. They also produce the rankings of the biggest 50 facilities houses every year in their magazine.
Look at the credits of other shorts and see where they were done and, note the names of the actual editors who worked on them. You can approach an editor directly to work on your film and then, together, go to the bookings department to see what buy phentermine kind of deal can be done.
Some post houses have reputations for helping new filmmakers. They include Molinare (London), Rushes (London) who also have their own Rushes Soho Short Film Festival and The Farm (London). Feel free to recommend places weight loss pills here to others.