akerosid - you're right.
MarkD - what are you on about? FR are an Irish airline and do a lot more flying from STN than they do out of DUB. Should they let EZY take over for them just because they're Irish? And as for NCL, well the loads on that route never justified anything bigger than a Dash 8 anyway. In fact, the only two routes that are no longer on the schedule (since summer 2001 anyway) are EWR and ARN.
It's not so long ago that a lot of EI continental flights went through both MAN and BRS, so the idea of EI flying out of a UK airport is not exactly new. If there's a commercial opportunity out of LHR why not take it? I'd also reckon EI have more slots into LHR than IB would, and there's nothing to stop BA codesharing on it (never mind the fact the crew are cheaper too!) BD's LHR-DUB isn't doing all that well (despite the timings you cite.)
My take on it is that GLA and EDI may probably drop to one daily service, but I wouldn't bet on it. It's a fact of life that when FR setpped onto the routes to fight off GO, it killed off a lot of EI's traffic. LCY will go with the 146's, and 3 daily flights to LGW from DUB with BA is probably enough on that alongside FR's service. It doesn't make too much sense to continue a high frequency service as BA continue to relocate their long-haul services up the road to LHR. In the meantime, the capacity is redistributed onto increasing frequency elsewhere and giving the flexibility to introducing further new destinations.