The ceremony choices are actually alot nicer than I expected, to be honest. I just envision your typical City Hall wedding where its "I do." "I do." "Sign this." "You are married." But it wasn't like that at all.
I would still suggest you call your local Registry office where your wedding will be located. Once you let them know you are here on a Visa, they will let you know where to give Notice, along with the phone number to call. The local Registrar office should not only walk you through the info you will need, but you can still set up your date in advance. Its called a Provisional Booking. (This comes in REALLY handy if you don't have your fiance visa yet. or need further proof a wedding is actually happening.)
Then you will need to call and make an appointment with the office to give Notification. Both you and your fiance go together. You are interviewed together and then one on one. Don't worry, its basic information about you and your fiance. Its not an interrogation.
Once its done, there will be a Notification of your Intent to marry at that office for 15 days. Once this is done you can go pick up your certificate and take it to your local Registrar where you are having your wedding.
Your Registrar will also be supplying you with choices for your wedding. You should be able to supply them with "music" to play - usually at the beginning and end, but they do not stop and start it for you to come in at a specific song, or point in the song. You will most likely be able to choose if you want readings and you will be able to choose if you want standard vows, or write your own.
I'm babbling at this point but I do have to say, Our Registrar wedding was as lovely and laid back as we wanted it. It took me longer to get ready to walk down the hallway at the Registrar's office than it did to actually get married! 7 minutes and I was a Mrs. LOL. But it was terrific.
Good luck!