there aren't even that many A320s left to be delivered.
Well, according to the usually reliable Jethro's, there's 2 more confirmed deliveres with 10 more options.
Certainly, something in the Regional Jet (RJ) space, such as 318's would open up some new airport pairings, like a return to London City ... but would the passanger numbers be there for smaller airports?
Perhaps sourcing a single asile that could TA from Cork or Belfast with half decent loads would be a better idea. Perhaps limited seating 320/321's with IFE.
JAS