British Expats - Returning to UK, child applying to Sixth Form

I've read several of the threads here, and it would appear we are likely in the clear, but I thought I'd detail our specific situation and see if we might need to change our plans.

I am American, my wife is English. All of our children have had their births registered in the UK, and hold UK passports. We have been working towards settling in the UK over the past few years. We now have a property, and my wife and children are settled there full time since Spring 2015. For a number of reasons, I may not be able to join them for the next year or so. Prior to settling, we have "back-and-forthed" numerous times since 2010, with several extended stays in the UK.

My eldest child has been using a distance learning program based in the UK, and is half way through completing her GCSEs. She has already passed 3 tests and is well on her way towards completing 4 more in the Spring of 2016. We have elected to have her complete the distance learning program as she is doing well, and we don't want to throw off her rhythm if you will.

This past Summer we began looking at and applying to Sixth Form colleges in the local area to our flat. Up until now things have been going smoothly, and my daughter is excited about the prospect of moving forward in Autumn of 2016.

That said this past week we have received several inquiries from the admissions office of one of the schools we are interested in. They are specifically asking how long we resided in the US prior to my wife and children resettling, and are asking for detailed dates.

It would seem based on what I've read that my daughter should be considered a resident, with only the 3 year requirement for university being a consideration. However upon looking at the admissions page of this college, they do have information regarding tuition fees for "international" students. They also specify that students who have resided in the EU for 3 or more years are treated the same as a "home" student.

TL;DR

My daughter is a UK citizen who has lived abroad until recently, and is now wishing to enter Sixth Form, will we need to pay tuition or should she be considered a "home" student?