Training west of London

I'm possibly going to be in the area just north of Heathrow (Uxbridge) for 3 or 4 months starting in February.  Since I'll be there that long, I'll have to figure out how to train in London.  Is there a pool around that I can swim in?  Is it safe to bike on the local roads?  Is there a bicycle group that I can ride with that is reasonably fast?  Anyone out there looking for a training partner?

Cheers.

edit:  ps.  I'm looking for a place to live if anyone needs a flat mate.