We got our fiance visa with a one line mention of our intention to get married in January 2009, small ceremony in Devon. It was so important to the application that the visa was issued and dated from the issue date so that if we had gone ahead with the ceremony in January, Daisy would have been an overstayer.
Indicate your current thinking about the wedding - after all the purpose of the visa is entry to the country in order to get married - and as long as your other supporting evidence is strong I dont think you will have a problem.
