// Gromit - If these courts were to abide by the rules this country has framed for them then there probably wouldn't be a problem. //
I agree with you. They should work within existing laws. Marrying children at 12 is illegal in this country, so they can and should be prosecuted. But I am unconvinced there is a problem. The Iman in your link said he would marry a 12 year old, but there is no evidence that this actually happened or happens.
If both parties take a dispute to a muslim or jewish leader for arbitration, and as long as nothing illegal under British law is decided, then good for them.