Hi,
I used to work in Business development with salons in London.
The main points, have really already been mentioned here, but it depends what sort of area/ clients you want to work with.
In the City you will be working weekdays, not weekends, with professionals who will be interested in quick in and out services, lunch time services are very popular. There does tend to be a lot more money there, and actually not that much competition- most are directed towards men.
Or you could look in slightly more residential areas, which are very affluent, but people have more time and are looking for more luxury services.
But yes, competition can be hard in these areas, and you'd really need to have a bold USP so that you can stand out from the others.
Hth.