she-von, so sorry to hear about your visa refusal.

It seems to me to be a very weak case for refusal and I suggest you follow carefully all the paperwork and instructions for an appeal.
Please be very sure to stay within the given time limits.

The ECO's should know very well the limitations on submitting evidence of intent to marry. I feel you may have been very harshly treated and very unfairly treated.
As such I suggest you also prepare and send a letter to the British Embassy for the attention of the Entry Clearance Manager requesting a reconsideration of the ECO's decision.

What evidence did you submit relating to the wedding?

As mentioned, the ECO should be aware that the law relating to marriage in England and Wales does not allow for any arrangements to be made with a Registrar until the foreign national has arrived in the UK. Of itself, a booking at a Register Office or church is not proof that a marriage will take place.
However the ECO can expect that you actually made some tentative plans for the wedding.
Any evidence at all, however small, that's available to show that wedding arrangements are in hand will help.

Did you include any facebook messages, e-mails or texts that specifically refer to wedding plans?
Any quotations for venues/cakes/transportations etc?

Finally, do remember that appeals can take a long time to happen.
Also that having been previously refused a visa does not prevent you from making any further applications. Each application is reviewed on its own merits and on the supporting evidence supplied at the time.

Did the ECO give any other reasons for refusal?