First of all, really funny typo, I didn't know you could rent cats! Second: it depends. In EU the national license is international across EU. ~~But in UK (thanks brexit) I think now (or soon) you'll be required an international driving permit to drive in EU with a UK licence.~~ I was wrong, things changed since last time I checked, thanks for correcting me.

It's really down to the agreements between countries in the end

It depends on what license you have. Some countries have agreements that licenses are interchangeable but realistically they never can be because traffic laws will be different in different parts of the world.