OK, I'm not sure I agree 100% with your lawyer about you having the right to inspect his property. If it's a one bedroom flat, he doesn't have a separate room for them, so how would you visiting demonstrate this/ reassure you anyway?
He either sleeps in the same room as them, or he doesn't. Unless you stayed overnight you would not know whether this is the case or not, which is nonsense.
It would make more sense to me that the girls slept in the bedroom as then he has the rest of the flat to himself when they are asleep, given that they will go to bed a lot earlier than him.
The only way I can see that you can police this is to ask the girls to tell you where they slept. I appreciate you don't want to ask them, but I cannot see another way. You could even send them with sleeping bags and a blow up bed. You can get these for a few pounds online. If after the next time they don't sleep separately to him, then you have grounds to ask to suspend overnight stays given that he is in breach of the order.
But I don't see how you can police this personally, as you cannot be there all night.
I hope that this answers your question?
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