DH overprotective over dd(11)

No it isn’t. It is a parents job to start the process of teaching their children how to keep themselves safe - by giving them the tools and confidence to move forward in life in a gradual and mature way. Giving them increasing levels of responsibility at a rate they and you are happy with.

And that will be different for different children based on many different factors and will be different for siblings

Add your DD voice and yours to the mix and move slowly but move.

It’s a parent’s job to raise their children to be functioning adults, to the extent possible.

Wrapping them up in cotton wool isn’t going to achieve this. Children need appropriate independence.

The way I see it, it’s a parent’s job to keep their children safe at all costs. Your DH is doing his job.

Well, whatever has happened to his other daughter is clearly steering his mindset. If something terrible and traumatic happened to her then it’s no wonder he wants to be extra vigilant over the other child to prevent something similar happening. It’s hard to know or judge without having the full picture.

Why does he feel like his parenting opinion is more valid than yours?

Sounds like this is very much about more than this one situation, but I’d use this opportunity to discuss with him how you need to make joint decisions on things like this, it’s not in his gift to think he can make big decisions like this and not be open to discussing with you or coming to a compromise.

We’ve had a couple of children come away with us, twice when my children were in Primary and once when in Secondary. We’ve also had a number of their friends sleepover.

However, had it been the other way around and my children were asked to go away with their friend’s family, I would have said no. DD has stayed at others houses, but only when there’s a group of them staying - fortunately she hasn’t been asked yet, just her.

I simply don’t trust anyone enough to risk it.

Days out with friends are fine though, either with friends family or just going shopping together etc… they don’t seem to have a problem being picked up and generally contact us throughout without us asking anyway (usually for a money top-up!)
Now, they go to ‘teenage’ parties 😬, but so far, so good. Dropped off and collected - they ask for this.

Your DH is right to be cautious. Year 7 is young.

I think you can meet in the middle. I wouldn't view it as "challenging" him, just discussing your individual concerns and finding a compromise. Explain your viewpoint and try to nudge him towards allowing her more independence. Maybe she takes the bus home with friends once, but he drops her off. You all sit down and agree that when she's out with friends, DH won't text unless it's urgent. Eleven is still fairly young so I would immediately assume his worrying is solely because of his experience with his other child. I think a lot of parents would give pause before allowing their 12 year old to holiday with another family alone, to be honest.

Is she in Y6 or at secondary school? Somewhere around that transition he’s going to have to let her practice being more independent. The risk is she has to become secretive or deceptive to try and have a normal teenage life.