I have series 1-3 of Coupling on DVD and it's one of my favourite comedy shows (I didn't buy series 4 because I didn't think it was as good after Jeff left the show). I sometimes catch the show on Comedy Central or Comedy Central Extra (on UK digital TV), but it seems to be on pretty late at night (around midnight) if it's being shown.
It's actually not based on Friends at all - the only real similarities it has are that there are 6 characters (3 guys, 3 girls) and they hang out in a bar! Unfortunately, it was billed as the UK answer to Friends (i.e. a similar type of sitcom), which everyone took to mean that it was a UK version of it (which is like saying ER is the US version of Casualty
)! The writer (Steven Moffat) actually based the show on his relationship with his wife (producer Sue Bertrue... hence the main characters being called Steve and Susan!) and has even stated that he was influenced by Seinfeld more than anything else in terms of the comedy.
I was living in America when the US version of the show was aired in 2003 and I'm really not surprised it only lasted 3 episodes before being cancelled... it was pretty dire
. They basically remade the episodes word-for-word, but the comedy just didn't work (and it was apparently considered too racy for US network TV!).