The only reason she wants to come back to a country that she obviously has no respect or love for is to take advantage of all the health and other free social services which no doubt, like idiots, we'll throw at her.
I suppose that she could possibly be allowed back - and then shot.
There is no way I am troll through all the previous replies to this but I wonder if as it seems she is a British Subject then how can they stop her from returning to the U.K.? Just make sure the police are there ready to arrest her preferably with all their homework done and evidence collected etc.
I understand the family originate in Bangladesh! It seems to me the answer is to deport all of them back to that country. If, as has been alluded to by JB the Father is a supporter of Anjem Choudary then the grandparents are obviously unfit to bring up the child, I would have thought deportation of the entire family coupled with a revocation of their UK citizenship is the correct course of action.
As the parents are duel nationals, revoking their citizenship should be achievable.