As to expense of removal: Bear in mind that you - or a beekeeper who takes the bees - will need to spend about $150 on equipment to keep the bees in.
Bees naturally propagate themselves, and with control on genetics and not much time or effort, a beekeeper can arrange to "split" bee colonies. Feral colonies are a random risk, as 15th member said. And depending on the situation, it can involve construction demolition, heavy lifting, and time which is valuable.
As to removal techniques: Most removals require a bee vac to remove bees so that 1) the bees are more docile during the removal 2) the comb can be more easily saved. A shop vac is too strong and will damage the bees. If it is a large colony, I have not been keeping all the brood (unborn bees) because it is too much for the colony to handle after the injury. A cutout takes a lot of tools, and much TLC for the colony after the change in habitat.
Since the colony you have there has brood already, it won't leave them behind, even if the bees see your nice box. Here's an idea: you might get them to expand into a beehive.
Is your sprinkler control box a plastic shell? If yes, and you want to become a beekeeper, you might:
1) get a $16 smoker from ebay and a protective veil, and take all safety precautions by doing your research.
2) Buy a hive, frames, bottom board, and Imirie shim with a notch, and outer cover.
3) Prepare the hive by removing the bottom board, and setting the hive body on two wood runners (so it doesn't rot over the next few weeks).
4) Remove the sprinkler box lid and set the hive/shim/lid on top.
If the only way out for the bees is to go out of their nest is
through the upper notch in the hive, they may move up into the hive. Or ....they will move up when they run out of room in the sprinkler box. It's sort of a Carl Hogan trap out.
Or maybe you could dig out & lift up the plastic sprinkler box, and put it on top of a hive's inner cover, and then the bees might move down into the complete hive.
Just some thoughts, to avoid cutting everything apart, and instead letting it morph over time. If you want to learn about how to be a beekeeper....
http://leeming-consulting.com/SchoolNet/courses/beekeeping1.0/topic_one__an_introduction_to_beekeeping.html