Social dancing (tango, salsa, swing) groups and classes for young professionals in London?

I'm a young professional in my twenties working in London. I'm wanting to learn some form of social dance - along the lines of tango, salsa or swing - and make some friends in the process (a date would be a nice bonus!)

I'm not sure if I'm googling the wrong keywords but I'm not really finding the sort of thing I'm after. Simply put, I don't want to be stuck with a group of children taking dance lessons... or middle-aged couples in their fifties.

Any pointers in the right direction would be much appreciated.

Thanks!!