This whole question arises from one big failing of the judicial system in this country, "Wrongdoers have rights too"
Just what do you have to do or say in this country before the judiciary says "Sorry that won't wash, your getting the book thrown at you"
There has to be a cut off point. Many lawyers, in Britain, defending the indefensible have to resort to finding loopholes in the law to get their clients off as guilt or innocence no longer seems to be the issue. You only have to look at that trial a few years ago now {I think it was Guinness or something} the guy in the docks lawyers had the jury believe he had basically gone ga ga and was not fit to stand trial, he must have put on a convincing act as the jury bought it and the case was dismissed, about 3 weeks later that same bloke was chairing a large corporation earning mega bucks.
These girls WILLINGLY joined ISIS they knew what they were doing, they knew where they were going. The lawyers would argue they were 15 years old minors therefore didn't know what they were doing {put expletive here}
Leave her where she is and revoke her citizenship, bring the kid back, as that's the only innocent part of this mess, and put it up for adoption.
For all we know her "husband" has probably put her up to this, she gets repatriated back to Britain, lives off the state, meanwhile he like many other ISIS fighters have merged into the background claiming to be a refugee, mingling with the very people they have terrorised for so long, and sooner or later he will find himself in Britain playing house with his "wife and kid" yet another sleeper cell!