Hate to say this but they are probably annoyed at having been in the cattery for so long - feelings of abandonment. They didn't know that they were going to see you again. They are probably just showing their annoyance at you. Maybe something happened either in the cattery or on the trip over here.

I know my cats get their noses out of joint after having had to go to the vet overnight! And when I have been hospitalised for a few days, they wreck my house - they do things they know they wouldn't get away with if I was home. You just need to restore order in their lives, love them and let them know you are the boss. If they try to bite you when you are petting them, tap them on the nose and put them away from you, or walk away yourself. If they are trying to slash you with their claws, do the same thing. If they do diving attacks, spray them with a water gun. LIkewise if they are doing naughty things that they wouldn't have done before.

You could also lock them in the laundry for short periods when they are naughty, eg 30 mins. (One of my cats was really wilful and I would have to put him in "time out" (my ensuite in this case) for 5 to 10 mins - just long enough for him to calm down and think of something else. When I let him out, I would give him a bit of a cuddle or feed him a nibble or both. Always worked.)

Just remember to give them love and maybe some treats and make some "cat-time" so that they know they are still loved. It is probably going to be a while before they fully trust you again and will also take patience on your behalf.

Rather than the plug in, have you just tried buying a couple of those catnip toys, preferably about the size of a small banana - something they can really smell and hold onto.

Personally, I would get them out of the cattery sooner rather than later. Nothing will be gained by leaving themthere. The problem could be exaccerbated by them being there again so soon.