My cat is bullying next doors kitten!!

[Ineverpromisedyouarosegarden]

How on earth do I stop my big adult Tabby going next door and battering their windows and scaring their Kitten into hiding under the sofa?

My cat is a neutered female aged about seven. The kitten is about ten weeks and hasn't been let out yet.

My cat is apparently quite vicious towards the kitten through their window.

Our older cat did exactly that to our new kitten while the kitten was kept separate when settling into the household. We blocked the view through internal glass doors with some paper which restored a bit of peace, but the older cat went and sat on the windowsill of the room instead and glared through it.

Once we introduced the cats, the older cat proved herself to be a massive wuss and ran away from the kitten. Now they batter the windows at each other through the internal doors, kitten thinks it's a great game.

Not sure there is anything you can do apart from keeping Tabby inside. And neigbours could move kitten to another room, shut the curtains, or at least block off the lower half so Tabby can't see through.

You can't do anything about it. Both cats are being cats. Cats can't be trained to behave differently or told off. They have a pecking-order and will have a scrap or two to establish which one is in charge. Your cat may not be the winner - the younger one will be faster and keener.