I find the idea of taking someone else’s children on a day out, and not telling them where very strange indeed. Fair enough you may decide on the spur of the moment to pop to the shop for some sweets, or visit a park close to your home for an hour, that’s slightly different. But taking children to a town and their parents not even knowing where they? That really doesn’t sit right with me.
The fact that you took them to a place you know your daughter didn’t want you to, is quite frankly ridiculous. You are not their parent, and you do not get to decide what’s best for them. Your daughter doesn’t owe you an explanation regarding any of her parenting decisions. It is your job as a grandparent, and more importantly HER MOTHER, to support her decisions, and reassure her that not only is she doing her best, but doing a fantastic job.
If I remember correctly, I commented on a previous thread where you discussed your daughter’s & grandchildren’s bereavement? Perhaps some of what you describe as ‘controlling’ is her still navigating her way through that horrendous grief. Perhaps after losing her husband she has become slightly more protective of her children?
Apologise, sincerely and profusely. And for as long as you need to. You will have to take your lead from your daughter from now on, and be patient if the time you do get with your grandchildren is different for a while. You have broken your daughter’s trust and will have to work to build it back up, as long as that may take.