Pete, there had been a campaign to continue with it being obligatory for religious groups which wanted to carry out the ceremonies (whatever they were called in law or in their belief) NOT to be able to. I don't think anyone wanted to make it obligatory for religious groups which did not want to to do so, though I know that those who wanted to stop Reform Jews, Quakers etc from doing so were presenting the issue as if allowing them would make it compulsory for everyone else.
I can't imagine that any same sex couple would want to have a ceremony in a place which regarded that ceremony as seriously wrong, anyway.
I'm glad that legislation now enables religious groups to do what they believe is right, while not forcing anyone else to do what they believe is wrong. Seems sensible to me.
I don't think this issue is, anyway, as important as a church banning mixed race marriages, which is what the OP was about.