Taking Beekeeping to a Higher Level

I do enjoy life in the Cotswolds, and particulaly the challenges that pop up from time to time once word gets around that you are a rural beekeeper.  I got a call from a construction company with a bee problem the other day.  They are renovating an old farmhouse and have discovered that not all the previous tenants have moved out.  It would seem that a colony of bees has made itself at home in one of the chimneys.  I usually view such requests with some trepidation.  Most beekeepers, me included, tend to like to have both feet on the ground when dealing with bees.  Catching a swarm in a tree can be challenging and often taking the easy way out (leave them to it!) if they are too high to be retrieved safely is the the best option.
With houses, chimneys and roofs there is no "leave them to it" option.  Fortunately the construction company in question is very keen to do whatever they can to conserve wildlife and particularly ensure that bees are looked after.
When I arrived at the site I realised that this was not a "balance on the top of a ladder" type job and after signing in and getting my hard-hat I was guided to a two storey ladder and onto scaffolding.which has been placed around the house and gable end chimney. On a gloriously sunny day with wonderful views of the surrounding countryside, I could see what attracted the bees to their current property!
Donning my bee jacket I went up on the chimney scaffolding and had a look at the situation.
There were a lot of bees coming and going through gaps in the mortar on the face of the chimney.  Aparently there are two flues, one that will be relined and opened up and one that has been blocked off, Fortunately they are in the blocked off side and by the number of bees I would say that they have been there since at least last year.  It is probable that they will be swarming soon.  As you can see  the entrance is actually at a very convienient height given the scaffolding! However it would be better to try to avoid taking stone blocks out of the chimney and pulling them out enmasse if possible  Having discussed timescales I was very releived to discover that there is plenty of other work that can be done on site so we have the luxury of a few weeks to sort this out.

I am proposing to put a cover over the entrance with a short pipe attached which I can insert into the back of a spare broodbox with some foundation and old comb to make a new hive.  This will have the effect of moving the entrance to the otherside of the brood box and encourage them to expand the nest out into the box.  After a few days I will put a no return valve in so that all the flying bees and newly hatched bees will have no choice but to take up residence in the box and hopefully the queen will then join them there and establish this as the new home.  After a few weeks there should be no more bees in the chimney and we can then seal up the old entrance with mortar and take the colony back to the apiary.
That's the plan anyway.  If any of you beekeepers out there have any suggestions or "gotchas" that I might need to consider please leave comments below or talk to me on Twitter.
I will, of course, keep you posted on how this works out!