If, and it's a big practical if, she can make her way back to Britain, she will have to be guarded carefully so that she cannot act as a centre for ISIS sympathisers who are the great danger now that the fighting Daesh are disbanded.
I have no idea how a lifelong extreme right wing Muslim criminal might be turned into an honest citizen, but her new baby will need to be removed from Daesh influences, and fostered.
The alternative, leaving her stranded in Turkey, if she should manage to make her way there, isn't possible as we have a moral duty if not a a legal duty to deal with our home grown criminals.