Rento will do what they always do, rip you off!
The quality of thier operatives isnt good.
The law states if a bee colony has been treated (killed) any entrances MUST be blocked up as soon as is reasonably possible (preferably on the same day as treatment)
This is why i am asking the questions, as it stands at the moment, if someone calls me to sort out a colony, if they are in a cavity or somewhere equally difficult to get at, then the only cost effective solution is to treat them as i would a wasp nest, then secure all entrances to prevent any other bees from gaining access and potentially killing another colony elsewhere.
I do know a lot of pesters dont block up after and it could be a real problem. There was a case recently where a pest controller was taken to court, accused of indirectly killing someone elses bees by cross contamination in this way. Whether this really was down to the pest controller is debatable, as from experience i know that the insecticide used to kill wasps wouldnt kill a whole hive if just a handfull of bees returned contiminated. In fact i have my doubts that they would even make it back to the hive unless the hive was really close.