Please remind all concerned (especially the groom!) that mobile phones should be turned off before entering the building where a ceremony is to take place, otherwise you could have the "Flight of the Bumble Bee" or "Old MacDonald" going off part way through!
An exception to this can sometimes be made in certain circumstances, provided it is agreed with the Superintendent Registrar in advance. With such an international population it may be that people special to the couple are unable to cross the world for the ceremony.
They could be able to hear and see what is happening if they are telephoned just before the start of the ceremony from a mobile telephone you provide, this can be held by the person conducting the ceremony.
If they have internet access they can always see pictures of the ceremony rooms in our Register Offices.