I think it's fine to bring children to restaurants in the evening and there is no problem.
I have seen children at Calis restaurants and in Fethiye The good thing is, you can get up and take the kids for a walk, a wander around the shops, back to the accommodation etc.,
The key here is Scunner, you have not been to the Istanbul. So don't have any ideal of the layout. It is an open air restaurant but the space is used well and filled so no open areas.
Firstly, you get picked up by coach (around 6.30pm) and are take out there. Once dropped off, this restaurant fronts right onto the main road and sits on a S bend in the road. The stage with the musicians, sits in front of the main road, so not possible to play there. The back, where the toilets are has a swimming pool, which has no cover or railings and then chalets which are rentals. So, there is nowhere a child could run and play safely. Once there you cannot pick yourself up and go anywhere else, basically you are there until the coach comes back to pick you up around 12.15-12.30am.
Snowtop, I think you are right. When you have had your family and then once again have the freedom to go out and enjoy yourselves, without worrying about the children, you revert back to the time when you did not have kids and you realise what fun adults nights out are.