This has probably been done before but my best friend is separated, not divorced, just living apart and both got new partners ... still same surname as husband, but if she takes her daughter on holiday abroad, Spain, without the father does she need officially signed and notarised documentation, or not? They're all British with British passports - thanks
Nope she doesn't, we've been away 9 times now with SS (husband was married previously) and we've never ever been challenged. Even when my surname was different.
Your friend can take a letter to be on safe side, but it's entirely up to them. As we speak we are on holiday with SS and DD abroad and no issues at all and no letter from SS mum. SS flew last month abroad with his mum and her new bf, again no issues and no letters from us.
Does she have the same surname as her DD? If so, no documentation needed. I've taken my DTs abroad 3 times since we split, they have their Dad's surname not mine. I've had questions from border officials but I've yet to show paperwork (I've had it ready in my bag but no need...so far).