If you are editing a users profile and setting the Automatic EOT Time, you can use any date format allowed by the PHP strtotime() function. However, if you try to enter the UK date format of DD/MM/YYYY and then save the changes, you'll notice that the format is parsed as MM/DD/YYY (US format), or not parsed at all.

This is due to the way that the PHP strtotime() function works. It assumes that if the date contains slashes then it is intended to be a date in the US format (MM/DD/YYYY). However, if the date is formatted using dashes or dots (DD-MM-YYYY or DD.MM.YYYY), it will parse the date as a UK date.

So when using a UK date format, please use dashes (-) or dots (.) instead of slashes (/).

Automatic EOT Time: UK Format