Pet remedy is brilliant, I’ve used it with animals from dogs and cats, to bearded dragons and hedgehogs. It seems to work on them all, and the local rescue centre are getting through dozens of bottles and plug ins.
Don’t expect a 100% calming effect immediately, nothing works that well, but it should at least take the edge off. With bonfire night coming up, it’s best to start dosing the house and especially your pet’s bed/crate/room a week beforehand to get the best effect.