Ask the SWO - he is after all the Guardian of all things ceremonial. If he says yes, then do it. If he says no, then don't. I mean you have to ask his permission (and OC RAFP) at the end of the day to wear uniform for a wedding whether you're the one getting married or attending. Good luck for the day and best of luck for the future. Hope the sun shines hot and the wine pours cold