I notice this morning Serco are digging up Vauxhall Street near the junction of Kennington Lane to put in a docking station.
It's unsurprising there's demand in that area. There's a fair amount of housing, but the cost of the short trip into town by tube is an eye-watering £1.80 each way (Zone 1 only) on Oyster prepaid. Even with daily access (£1/day), cycle hire would save you £2.60 a day, or should you elect for yearly access at £45, you'd save £800 a year, give or take a few sick days.
Even if you lived in Merton (Zone 3), you could profit by getting off the tube at Kennington and cycle the rest of the way. The difference between a Zone 1-3 single (£2.70) and a Zone 2-3 single (£1.30) is - uh - £1.40 each way, so daily-access cycle hire gives a daily saving of £1.80. Again, the thriftier yearly option would net you savings of over £600.
(all calculations based on Oyster prepaid single peak tube fares, 2 journeys a day, 5 days a week/48 weeks a year. Helmets not included.)
Next up, I did a (very unscientific) cycle count at lunchtime, in a half-hour walk around the West End. I counted 25 cycles, of which 6 were hire bikes. It seems not unreasonable to assume that most hire bikers would not have made their journey by bike were it not for the hire scheme, so the numbers indicate the scheme may have increased the modal share by 25% or so. Bear in mind that casual access is not yet available, so demand is artificially suppressed particularly in the middle of the day. What is rather shocking though is how few bikes of any sort I saw being ridden, considering the fact that motor traffic was moving at its usual torpid rate. There are lots chained up to street furniture - Westminster Council can't be bothered with cycle parking because it makes them no money - but on the roads, bikes are rarer than hen's teeth.
Lastly, it seems, according to the Standard's estimable Ross Lydall, Tfl have been indulging in some - er - Enron-style accounting with the numbers of hire bikes.