Although magic lantern slides were most famously used professionally by schools, universities, churches and lobby groups they were also used by amateur photographers. The glass slides, 'masks' for displaying the image and fixing chemicals could be bought from local photography stores. Anyone with darkroom could have a go.
What makes this slide unusual is that it is in colour- by this stage, most amateurs had abandoned magic lantern slides in favour of smaller, 35mm film. The car's number plates are pre-1964 which gives us an idea of the last date this slide could have been made.
Regardless of how it was captured, this photograph is of a wonderful 'Kiwi' caravan holiday. Where it was taken remains a mystery.