Just an update on this. It appears Plex have pushed an update to Live TV. When you run through the setup process you can now select from multiple programme guides:

 

 

 

 

 

 

One of which appears to be Sky TV! The channel mappings require a little bit of fiddling but so far from my tests the EPG appears to be more complete (can't test Police 10/7 as this has finished now.... sob). Might be worth a go for people?