Adding second y axis in a powerpoint chart

Hi All

I'm using Powerpoint for Mac and creating a series of charts for a client. One of the charts requires two Y axis, one on the left with a range of 50-400 and one on the right with a range of 50-150.

Is this possible? I know it used to be in earlier versions of Powerpoint but I cannot find a way in this latest version.

Hoping someone knows an answer!

Simon