Serco are terrifyingly bad at providing a working service. After having to deal with Serco support during a call to fix a problem with their school information management platform Facility CMIS, I actually think AOL support is pretty good, despite the fact that you probably pay £1.50 a minute to be on the phone with them and £10,000 a year for software maintenance and support for CMIS. Not to mention that CMIS itself is a horrible mess, it was designed so you were forced to go on training in order to know how to use it for basic things, never mind actually managing it. It's the least intuitive and user friendly system I've ever had the misfortune of managing and you have to think twice when managing it because one menu click that says one thing might mean it'll do something else that is potentially fatal to the data contained within. It's lost when that happens, Serco's support team is worse than PC world's aftersales service.
I've dealt with the best of the best support services, and I've also dealt with the worst, the worst being Serco. I'm not surprised this didn't work. If plotted for Winter launch, shows a great lack of confidence in their own product, they know they put a half-arsed attempt in to making it a success, and as a result it didn't work.
Best thing London can do is write-off everything Serco has done for them, and contract a firm which prioritizes their clients, and not their bottom-lines.