I can thoroughly recommend
British Military Fitness.
They do stuff in lots of London parks, I used to go to the 7am Hyde Park sessions on my way in to work. Having children has made that more difficult.
However if we can drum up enough local interest we might be able to get some classes on e.g. Peckham Rye Common or in Dulwich Park.
There are three levels - blues - reds - greens, with increasing demand on fitness level respectively.
I can definitely say I've never been or felt fitter than after 3 months of it a few years back.
Or if we can't get enough people for a class, I'd be happy to go halves or thirds if anyone wants to hire one of them for personal training.
--------------------
_____________________________
Nic Price -
beatnic.co.uk