Latest word is that the 320 will return in March.
I wouldn't pay much attention to "the latest word", what with March 2011 being a long way away, the evolving Aer Lingus Regional story, the possibility of the tourist tax being revised, the volatility of Ryanair's whims (scathing Cork's charges but then throwing in a 2nd aircraft for the summer), and most of all because "the latest word" has often promised the imminent arrival of an extra Aer Lingus A320 but now instead we're losing one.
Also, I personally wouldn't be surprised if MAN and BHX were to become Aer Lingus Regional routes.
All that said, maybe we're getting a bit carried away here, assuming we're losing Aer Lingus A320 number 4. Maybe its schedule just isn't loaded yet?
It could then operate Manchester, Birmingham, Rome, Alicante, Faro.