"What is a celebrant?"
As a Buckinghamshire Wedding Celebrant I am not affiliated to any particular religion. You will still need to go to a register office to make your declaratory and contracting words and to sign the marriage register in front of a registrar and two witnesses but this can be very short and very basic. But from then on, if you choose a celebrant, it is your choice, your ceremony. I work chiefly in Bucks but am happy to travel within reason.