The easiest way for New Zealanders to renew their Visas back in the 1960's was to leave the U.K. and get their passports stamped when they returned. It saved hours of queuing down at the Croydon Immigration Centre - and was usually fairly entertaining one way or another ...
Here's Kodachrome Super-8 footage of my final renewal in 1969 - successful again, luckily - but only for another six months.
This footage pairs with 'A Weekend in Amsterdam', listed above ...