After Australia’s clock change last weekend, the national broadcaster has published an article about the Eucla time zone:

https://www.abc.net.au/news/2019-04-08/this-remote-stretch-of-desert-has-its-own-custom-time-zone/10981000

Sergeant Chamberlain said when it comes to life on the Nullarbor, the custom made time zone was at the lower end of quirky.

Some interesting snippets of information include a rough description of the geographical boundaries...

The time zone exists for about 340 kilometres and takes in the tiny roadhouse communities of Cocklebiddy, Madura, Madura, Eucla and Border Village.

…and an indication that the zone has definitely been in existence since before the 1970 cut-off of the database:

Mr Pike has lived on the Nullarbor for 47 years

[…]

'Why'?

"Good question," Mr Pike said.

"I don't even know that, and it's been going for over 50 years.”

This doesn’t change any of the existing data, but could be useful as a reference.

Cheers,

Gil