Interesting about the A321-LR.
Looking ahead to Summer 2020 there will be 2 Aer Lingus A321-LR based at Shannon.
1 for the daily JFK route, 1 for the Boston route.
It appears that 1 of those will also do a cheeky SNN-LHR-SNN in the mornings, every morning in Summer 2020.
The other will have room to do a short morning rotation too, in theory...
Meanwhile the A320 which usually does 3 SNN-LHR-SNN per day, will now start it's day at 12:25pm, which is indeed not very efficient.
Malaga seems to be operated by a Dublin based aircraft on a W routing.