Answer

Both we and the supplier need a named contact, along with a telephone number, of a person who will be on site to accept the delivery.

 Once the source arrives with our supplier (they are manufactured in Germany and shipped over), the supplier contacts us to say it is ready for delivery and we then contact the customer to arrange a delivery date. The named contact must be on site that day, even if they can’t personally accept delivery. Obviously it’s better if the named contact can sign for it, but I think as long as reception can contact that person at the time, and they confirm that they are on site and that reception can accept delivery, it should be OK. It's much better if the named contact can be there in person though, as the carriers don't like leaving radioactive sources at reception - or they may even refuse to do so.