Thanks for the detail Daniel, and everyone who has replied. This is a shame its gone.

I think there is an issue with documents changing. Maybe a case of documents not keeping up with changes. I get that, it happens, but not flagging it anywhere and relying on delving into History (good tip however) does put you on the back foot and you start to lose faith in documents you link to others for support and training. 

It should also be in release notes but I don't mind that so much in that it not being a feature I'd ever used I wouldn't have thought to check those retrospectively to see the status of the feature.

Thanks all...the "Bring back Sort by Likes!" campaign starts now, lol.