Sorry about the length of this - don't want to drip feed. I also wasn't sure where to put it. If anyone has an idea of a more appropriate place please let me know.
I have 3 year old DD who has never slept well and 6 year old DS who slept well right up to when his sister was born. If we had DD first I'm pretty sure she would be an only child.
Not only are our DC not sleeping but they are noisy. Run up and downstairs always needing another drink, shouting and screaming. We say no DD starts wailing very loudly. One of them will finally sleep the other one will wake them up - sometimes deliberately. We have tried bribes promising treats and we have threatened and withdrawn all sorts. Nothing seems to work.
They are getting worse. We are in a small house with only one and a half bedrooms. Moving isn't an option and even if it was we can't afford a bigger place . To begin with we put the DC in the big bedroom and crammed our bed in the single room.
This has been going on for a few months since we moved here. I knew one day the neighbours would complain, quite rightly in my view as they have a toddler themselves who sleeps in the room next to our two. Wish we'd had the guts to go and see them to apologise before they did. But how can you apologise if it's still going to happen? Now it's awful because they didn't complain to us but to the Community Safety Wardens. First we knew of their existence was when they called to investigate. 
Our latest attempt to improve things has been to switch bedrooms. We had to buy bunks to do so although we couldn't really afford them. Hasn't worked
I end up with at least one of them in the double bed with me. DH is on the sofa downstairs most of the time.
So our marriage is going down the pan, not just the separate beds but the whole situation and particularly the lack of sleep causing rows.
The neighbours have just had cavity wall insulation installed - feel terrible that they have had to go to the expense (hope they got a grant to do it). Don't know if it's likely to have made a difference, can only hope so. We rent and there is no way our agents would get the landlord to do anything similar. A complaint to them will have us evicted and homeless.
Tonight DD has been asleep with me for a couple of hours and DS finally about an hour ago. DD starts at nursery in January so hopefully this will help. We have been getting her up earlier than she needs to be in preparation and she falls asleep in the afternoon so it's not like she doesn't need the sleep. DS is being home educated at the moment - no places available at the local one, he is top of the waiting list. Keeping everything crossed for a place in January. I suspect and his last school suspected that he has an as yet undiagnosed SN. He paces around his room making whooping noises. The GP is the next step afaiac but we can't even agree on that.
I need to go for myself anyway and will probably go back on anti-depressants as I am not coping. DH is off work long-term originally for MH reasons but now has a physical problem stopping him going back. It really worries me that social services might become involved if both of us are being treated for MH alongside the Home Ed or maybe that would be for the best 