piatkow, I'm wondering that even with two wheels is even possible! Perhaps it's going to be a very small delivery area.
If you excluded some of the semi rural parts of the outer boroughs I reckon two distribution centres would do it but the drivers would be doing one delivery per trip most of the time.
Zones 1 and 2 only would be feasible but the distribution centre would be on some expensive real estate. I suspect that the coverage will be skewed based on the availability for a suitable large shed to use as the base.
Perhaps they should use pigeon power, there are lots of them hanging around doing very little...... ;)
Amazon say it covers 'Central London', which isn't officially defined. Could just be around the West End, City and Westminster areas, which aren't too far from East London and roughly equates to 'zone 1'.