I dont know. I mean why not? Why not having different laws in one country?
A country is just a territory. Different people? then different laws. Muslim marriage is different from the British mariage. So I see no problems in letting specialized courts intervene in such maters.
See this like a different contract. I dont see anything shocking in this.
And I think that the UK are pretty advanced in these topics. But of course, to avoid disputes and conflicts, they have one universal that rules the others laws if there is a problem...
I think it's a good thing.