PLEASE HELP

My husband and I are absolutely at our wits end with our girls at bedtime, they are 8 and 5 and they go to bed fine we do the same routine every single night teeth, wind down, story etc they are happy with that and settle down fine but then it starts – they share a room and the littlest makes the tiniest noise when trying to go to sleep and my eldest shouts and screams and they are up and down, up and down for at least an hour and a half to 2 hours afterwards, its constant fighting between them and our eldest screams at her sister and then comes and screams at us and it’s like my littlest is just doing trying to get a reaction we try and not give her it but my eldest just screams and shouts and won’t just ignore her – we then end up screaming and shouting because we just want peace, we can’t get tidied up or time to ourselves sometimes it can be 10.30 before they are sleeping!

Any advice will be greatly appreciated!!