Thanks Sean. I was looking mistakenly in Develop mode. Duh! More stunned than me arse.

It should be there it is on my mac. You need to be in Library mode and in grid view to see it at the bottom, looks like a little paint can.

Sean gave a great demo with LR at 'Photo Day' including use of the paint can icon to quickly add key words to photos. I don't see any icon on the Mac screen version that is comparable. Is this feature available in the Mac version and if so, where is the icon for it?