Talk to me about bed time for 8 and 11 year olds

[origamirose]

Please help. My DP has 2 children aged 8 and 1 month and 10 and 11 months. They live with their mum and stay with us one night a week and every other weekend.
Bedtime is chaotic, late and invariably ends up in tears and tantrums. I'd like to work with DP to instigate a calm bedtime routine. At their Mum's they have separate bedrooms and during the holidays can turn their lights off whenever they want. I don't want to do that here - I like to have my own light off at 10:30 and would like at least half an hour with my DP before I crash out.
Anyone want to share their pre-teen bedtimes and routines with me?
Thank you.

dd is 8 and her schoolday bedtime is 8.15pm and at weekends it is 9pm

My 8 year old goes to bed around 7.45pm on school nights and anytime between 8 and 10 on a weekend (depending on how fed up I am). When DSD was 11 bedtime on a school night was around 9.00pm and weekend around 10-10.30pm.

If they're used to lights out when they want at home then you're going to have a fight on your hands to get them to go to bed when you want in your house. TBH I would say that on the nights they're in your house you may have to do without your half an hour with DP before bed, you do get your other nights free to be with him. I would definately make the go to bed when you have though, and not be allowed to stay up later than you.