The grounds for appeal will be that she has (had) a British passport and by law people can't be rendered stateless, and they may appeal the decision to revoke it anyway as politically motivated and illegal/unfair as she has not been convicted in a court of law.
But I think there may be enough going on to muddy the waters for some time - there is a suggestion now she was actually born in Bangladesh not London, there is the issue of the baby's father being Dutch and maybe his agreement is needed to the child coming here (may be difficult as he's either dead or in hiding) - and we can always drag the appeal process out then appeal the appeal etc