Help, my Siamese needs an ASBO!

[Littlemissindependent]

Have had my 18 month old Siamese for a little over a year now. She's, for the most part, pretty laid back, affectionate on her terms, massively attached to one of my older cats. However, since bringing home new kitten 2 weeks ago, Coco has turned into a delinquent she's like a sulky teenager! If she's not trying to kill the kitten then she's up the Christmas tree, pulling things over, following me around the house demanding attention and screeching at me if I dare to stop fussing her.
I appreciate she may be feeling left out since kitten arrived, but I've made a point of going out of my way to make sure she still gets the same amount of attention (if not more) as she always has. But it's no good. She's just jumped up on the bed, battered the poor kitten, so I told her off. She's stropped out of the room yowling in disgust and promptly gone to climb the Christmas tree. Again.
I have a feliway plug in and she's normally so good but I'm at a loss as to what to do with her atm. HELP!

How are the other cats reacting? Do you have 6 in total now? That's quite a lot of squeezing of territory.

In my experience, when a Siamese kitten moves in, other cats are a sort of wallpaper/fixtures and they either get on with them or ignore them. Grown Siamese are a different beast though. Most cats have a notion of territory as eg whatever they can see, hear or smell. Siamese, in my experience, regard their territory as whatever they think about.

mine regards anything that appears as up for grabs. "That's mine, ooh that's new - I'll have that, that's mine, that's mine" and fluffs up to something the approximate size and shape of a silver back gorilla if he spots another cat in HIS garden!

Do you have a pic Weeds? I love that image

Well of course it's his.

The fluffing up thing is funny. Coco looks ridiculous with a huge fluffy tail. I have just woken up to discover her asleep on one side of me, and the kitten asleep the other side of me, so that's progress in itself!

No pictures of fluffing unfortunately, as it's generally at the same time as he's barrelling down the garden, beating his chest and roaring at poor old Will Feral, the neighbourhood ginger tom. Will is very good at climbing trees at speed. Here's a picture of him watching TV instead!

She's very beautiful. You should obviously let her vent her spleen on the Christmas tree.

I'd never get anything done if my cat was so pretty, I'd be too busy taking photos for Instagram.

Weeds - so similar to mine. If a "nasty dog" so much as walks past the garden, he does his self important bum wiggle to it and waits until dog barks and then lunges at it
If I'm outside stroking another cat he hurtles out the window howling at me