Eloethan
The Islamic mediation courts are not part of our legal system Judaism also has mediation courts which are outside our legal system. Personally, I do not agree with either informal system since they reinforce male dominance. However, if we want to see the end to such systems we will not achieve it by marginalising and demonising certain groups. It will have the opposite effect.
The only people who can put an end to Islamic and Jewish courts are Muslims and Jews themselves because they are the only people to whom the laws are applicable. The laws are worth nothing in the UK legal system.
If people are concerned that women are being duped by the laws, they could try telling them, but it's up to them if they accept it. It's no different from Catholics who wouldn't use contraceptives or divorce as a result of religious belief, when the law of the land stipulated that they could.
Has anybody found any example of Sadiq Khan trying to extend Sharia Law?