Andy, what's the situation?
You might be able to remove them another way so it May(?) be worth describing what you've got (without giving away your lead if you don't want to).
I particularly like Plugs and Feathers as they give quite an elegant solution and (mostly) accurate cut, but they do use quite a lot of battery power.
Snappers are effectively gunpowder, so as Bob says it's worth going through EUG if you're considering using them. Although EUG are primarily concerned with High Explosives it would give you a good basis on safe practice.
You might even find that 'HE' are easier to come by in Yorkshire than Snappers.