Have search a lot but all forum threads I have found is marked as "Outdated".
So, how to add a meta title and description to the "collection/all" page (and also for collection URL with a tag at the end). Is it possible?
The easiest method is to make a new collection with the same handle. Then you'll have the ability to set those properties like you can with other collections.
Ha! Ingenious @Jason - now why didn't that cross my mind earlier. Thanks for the tip, going to be useful!