From what I've read they knew they were going to Iran and were warned off but ignored the warnings but 'wanted to find out for ourselves'. I couldn't care less about them.
They don't even live in the UK any longer. I understand that doesn't change their citizenship status but frankly if you are a grown up adult as they are and make your own choices as they did, ignore all the warnings because they knew better, the consequences really are their own. I'm sick of rights but no responsibilities.