The Church of England have the right to say this more than any religion outside the Christian Religion,
No-one has more 'right' than anyone else to have an opinion.
You see marriage was ordained by the God of the Jews and modern day gentiles christian Jewsl.
The earliest record of marriage is from 2350 BC in Mesopotamia. There are records of marriage in regions of the world centuries before stories about Jewish gods got there. Marriage, as so many other things, was co-opted by religion to try to control people's lives.
In their beliefs marriage is an ordination by God for his people and has no definition outside that meaning for Christians.
Then they can believe god's word carries weight, but that doesn't give them any grounds to try to establish rules for anyone outside of their club.
What you cannot do is make a law by man for man and give it the same definition as marriage ordained by God for just a man and a woman.
You're right, you can't, because when you make a law by people, for people, you can then actually enforce it with people rather than relying in imaginary future other-worldly punishment.
I accept the definition of marriage of a man to a man or woman to woman in the worlds law way.
I presume by 'world's law' way you are asserting some sort of naturalistic fallacy, which fails to two grounds: one, it's a naturalistic fallacy and two, it actually fails to recognise the widespread incidence of homosexuality in the natural world. You can accept any definition that you like, no-one's stopping you; we're just suggesting that the Anglican Church doesn't have a mandate to try to tell the rest of humanity which 'definition' they should be accepting of things like marriage or acceptable sexual behaviour.
But it will never be Gods definition as this is solely for a man and a woman becoming one body.
I've had a quick look in the cupboard, but it turns out I can't find any shits to give about what your particular interpretation of a particular god's particular definition (this time) of acceptable behaviour might be.
You can fit a nut and a bolt together naturally.
That's not natural, that's by design.
But two nuts or two bolts can never become one in their natural condition of creation.
Maybe, maybe not, depends on how adventurous you are (and whether you have a welding kit handy) but I'm pretty sure from decades of playing with Lego and Meccano that you can have a lot of fun trying.
So given the fact that marriage only really had a definition in religion for Gods people it had no standing outside this tenet of belief.
If you're going to say 'given the fact' it's probably worth citing a fact.
O.