One thing I didn't mention, almost all bike parks in London are just painted section of road, including the one where the bike was stolen, there is nothing except kerb to chain to.
That's true, but:
1. Where the council or landlord do make bars or similar available, few bikers make use of them
2. A simple disclock may well have stopped your friend's bike being ridden away quite so quickly. It, like my pound of butter in the fridge, might have put these particular thieves off entirely, leaving him none the wiser as to how close he might otherwise have come to losing his bike
Your friend took a punt on whether to add a further level of security to his bike, whilst he wandered off for his coffee in central London and decided not to. Very often we all do something similar. He lost his gamble this time around; it's as simple as that. Rants that thieves need to have fingers removed is just silly, not least when the owner has definitely not used his own fingers to help himself.
Do I think the circumstance - by which I mean the apparent use of an alarmed immobiliser was apparently easily bypassed - was unusual? Yes, I do. Do I think that the theft of a bike in under a minute - a minute which in itself might be part of an extended 30 or more minute period - is unusual? No.
Did your friend regularly leave his bike like this? I have no idea. From the story so far, it appears that he didn't see the theft (which took under a minute) taking place or hear the bike's alarm being triggered, only seeing the events unfold on a shop's CCTV afterwards. This suggests he was having his 'quick coffee' (whatever that means) some way away, out of sight and hearing of the vehicle. In short, he took the very common bikers' gamble and lost.
To rant about the police's unwillingness to drop tools and at once dispatch an officer or employee to view the shop's CCTV is disingenuous in the extreme, not least as your friend did not drop his own tools to quickly fit a disclock and thereby maybe speeded the theft of his own bike.
No doubt his insurer will now pay to make good his misfortune (and in passing any tardiness of the police) to fund his purchase of a new bike. The type or make of the replacement motorcycle will be a nice luxury for him to have. Let us know how this process goes, please.
We look forward to viewing the CCTV film, when he's uploaded it to YouTube. If possible, do be sure to add as much as possible of the film leading up to the theft, between your friend riding up and the time after it, presumably including your friend returning and looking at an empty space in his life. Just seeing the short minute of the theft out of context of the whole might well be less interesting and informative.