Wow! Thanks for all the comments. It is really helpful to hear from all points of view.
As a mum myself I can understand BM wanting to have all the "firsts". But on the other hand why shouldn't dh have some too? Why can't he be the one to see her face the first time she flies - he's missed out on so much. BM ended the relationship, he didn't ask to be separated from his daughter and miss out on so many things, opening her Christmas stocking, birthdays, first day at school. He can't even speak to her when he wants, it has to be in one half hour window once a week (and misses out if the x decides she isn't going to switch her phone on like tonight ).
NAMM - no she wouldn't have to have dh's permission. She can take her wherever she wants and whenever she wants.
Skinnycow - if dsd was hospitalised dh would drop everything and be there. If they lived locally we would be more than happy to help out, but it doubt that we would be asked. We would have her live with us if she wanted to. He will drive an hour and a half just to go to parents' evenings, he'll take a day off to go to sports day, he's a very committed dad. He only stopped contact with his daughter because his x refused to allow him to see her, and when he'd been assaulted for the 2nd time his solicitor advised him to stop calling to the house and it went to Court. His x however seems to see any involvement from dh as a complete intrusion into her life.
Good suggestion re sailing/driving - we are looking into that possibility but the cost of it might put it out of reach - and my sis is talking about Majorca anyway!
Loopy, thanks for that suggestion. I'm going to suggest to dh that he tries to talk to BM again. The other thing I'm thinking is that we'll just tell dsd that the holiday my sister is having is in term time and it just isn't possible for her to come out of school for it. Then her mum isn't the bad guy.
I think we're both really reluctant to go to Court, and my gut feeling is that it isn't the right thing because of the aggro and bad feeling it would cause, but like I said before I don't want dsd to feel we're letting her down.