FNRTTC?
We've suggested this before, but the last time I looked at the pricing, this could be expensive. I don't think they've revealed exact details of the cost, but the costs I've seen are not dissimilar to Paris' Velib, and that costs €151 for up to 20 hours, which would probably be the time you'd need to do a FNRttC. At a guess it looks like the London scheme would be at least £150 for a similar period of time.
I imagine the best way to go about doing a FNRttC on them would be to contact the scheme bods, and see if they'd be interested in doing some advertising using them. It probably wouldn't be a bad idea, since both the FNRttC and the scheme would gain from it, and newspapers, local TV etc like a suitably light story like this.
Personally though, I don't think I'd want to have to haul one of these up Ditchling!