I'm back to LineageOS.
As with any 'phone there were a few niggles with the Xperia running Sailfish. One major thing was the poor performance of the camera app in low light. However, the last straw was Android App Support crashing on a regular basis. This resulted in me missing an important time-sensitive to-do item (I use Etar, an Android app).
I'm going to investigate reverting to my original version of Sailfish (5.0.0.62), as AAS worked flawlessly.
Daily driver will be LineageOS, though.