Yes but as they are adults now, it will rely on them wanting to press charges. Now if a pregnant woman comes in to hospital who has undergone FGM, then they are advised that the new law means that if they have a daughter, they will be charged if child undergoes FGM. FGM can be performed at different ages too. I can't remember off the top of my head whether it's been decided on ways to monitor this (e.g. examining baby at crucial ages to ensure FGM not carried out or indeed before and after taken out of country) or if this is all still in discussions. Obviously not the easiest thing to monitor and does rely on police, social services, schools and health services working really closely together.
With regards to male circumcision opinions are divided. Personally I don't think it should be done for anything other than a medical reason and it is not done for religious reasons at my Trust (not sure about others but I think not). However, because it is not illegal, some urology consultants argue the case for it being done by a urology consultant for religious reasons because otherwise it is likely to be carried out by someone with limited medical knowledge which inflicts more pain and suffering on a child and indeed, could mean that said child may need to be referred to an actual urology consultant for corrective surgery. I can see their point too.