A friend is currently doing it...seems quite interesting to be fair, it is a foundation course...and most of it is taught at City and Islington College, but supposedly they have good links with the Met and good future prospects.
The practical side of it seems REALLY interesting though, he's always using cameras, taking fingerprints etc..but I guess you get a more deeper level of that in a full course.
I think they really just prepare you for a certain type of job, like the above mentioned.