I think that, as the royalists became more desperate, and power was concentrated in the hands of a single man, assassination attempts were going to be on the cards. There had been a plot to blow up the Directory, which London distanced itself from, but things were even more urgent in 1800. And easier, after all you just had to kill the main consul.

The British were good at making noises that such things should never be countenanced, whilst making sure all kinds of adventurers were well supplied with money. They could distance themselves if things went wrong, and take advantage if things went right. Same with D'Artois and his ultras.