Those are the ones technobots has started selling, so youll probably want to buy from http://www.technobots.co.ukwww.technobots.co.uk

That price doesnt include heat sink I dont think and a 2 Channel heatsinked version will set you back at least 70 pounds probably. Itll probably do about 15A with heatsinking so youll want to keep away from any bigger motors. Current limiting at 20A on the single h-bridge controller is probably too low for most decent featherweight motors.