I heard Ryanair may start LPL to Lviv
I don't think this is possible...Ukraine is non-EU, so a more restrictive bilateral is in place which is likely to restrict scheduled service operations between the UK and destinations in Ukraine to UK and Ukrainian carriers only (except, in the extremely unlikely instance, the Ukrainian government will play ball to change their bilateral air service agreement with the UK AND none of the Ukrainian carriers object to this).
All this said, I have been surprised for some time now that easyJet have ignored points in Eastern Europe outside of the EU (and the Ukraine is probably the biggest market available to the for UK originating flights that isn't Russia...which is a whole different ball park for traffic rights!)