Stereo to mono

I have a track where all the audio image is in the left with nothing in the right. Panning reduces the gain.
What is the best way of getting the image centre without loss?

Click on the name of the track (top of the panel on the left end of the track) and from the drop down menu select “Split Stereo to Mono”, then delete the silent track by clicking on the [X] in the top left corner of the track.

The behavior of a mono track is to play to both speakers. If that makes you nervous, you can duplicate the track you have. Select the track by clicking just above the Mute button and Edit > Duplicate and then using the same little drop-down, Make Stereo Track.

It will not actually be stereo. It will have no left-right separation, but it will be what you’re expecting.

And the short answer is no, there is no simple way.