Feral bee recovery

I joined my local bee group on Saturday 1st April for some demolition work. A feral colony had established in the space between 2 walls where a window had been bricked up.

The day was quite hard work but very interesting. At the end of it we had a Warre hive with some brood; plenty of bees and maybe a queen. We never found her so we can't be sure until the hive settles down.

It was a lot harder work than taking a swarm. I wonder whether it wouldn't have been better to make them voluntarily vacate the space. Maybe smoke and heat would make them abscond?