Hello, I'm about to purchase my first IWC. It's either going to be the Mark XV or XVI... a second hand XV is available, but it's a 2004 and has never been serviced, making me think it definitely needs a service and wondering how much a routine service for a little worn watch will be? I'm also wondering about the clasp leather band... I've a 16.5cm wrist. As I understand it the leather band comes in various sizes (small, medium, large). Does anyone know what size band I need as I haven't been able to try on the clasp band? Many thanks, Anthony