Ah, sorry tink, was supposed to come back and reply last night.
In my opinion, if you don't need his permission to take kids abroad and notified him out of respect and courtesy. I would say you have been reasonable. Do you lose anything by him knowing who else is going? What control will he gain? If the answer is nothing, then I would just tell him - let it eat away at him, it's not your problem and you should enjoy your holiday with your family.
If you think he will use the information in a negative and disruptive way, then tell him stuff on a need to know basis.
My understanding of the basic law is that if you have a residence order you can take your children out of the UK for upto 28 days without the other parents permission.
If you dont have a residence order you need to obtain the other parent's permission. i have had to do it myself. I just wrote a letter with details of the trip and dates and got my ex partner to sign it.
Its upto you which other adults you take with you, you dont need anyone's permission for that.
You could also contact the CAS or solicitor just to double check.