I am sorry Mr. Bean. I did not see this until today. I don't have a link, but temporary importation of many items, otherwise not allowed, is ALWAYS allowed for specific purposes. Extra paperwork is involved though.
Importing an item for demonstration or a competition. A car for a rally or a race. Foreign piplomats import their cars. under this provision

Most countries allow temporary importation with stipulation that the item would be exported after a specific period. I was able to import weapons into Singapore.