My understanding is that the OP is taking over responsibility for 6 hives which have been abandoned by their owner, who is untraceable.
They are sited on an allotment i.e. a public place.
That's why.
551 apiaries. I wonder how many actual hives that is. And it doesn't include all the hives which aren't registered. Seems like London already has plenty of bees and companies should be helping existing ones, not acquiring more. Not so profitable for the suppliers though and doesn't have the same...
Yes, perhaps you could persuade the powers that be to plant every spare bit of their land with bee friendly plants to help support their new bees. They're going to use a lot of energy flying up to the 3rd floor carrying their load. I believe 2nd floor is recommended maximum height. Unfortunately...