Aer Lingus don’t have a BHD pilot base. They shut it down ages ago. BHD is crewed from DUB but with local cabin crew.
Aer Lingus UK has its registered ‘office’ in BHD albeit a broom cupboard somewhere. They could easily transfer 320’s to the UK aoc and may do so with the LR’s for MAN as the 330’s might be going back to DUB.
I’ll be sorry to see the back of them if they leave the LHR route as BA are expensive and unreliable. EI do a far superior service on it.