Gazmo- where's the increase on BHX? Not challenging you just wondering as it looks similar to what I'd seen before for winter.
LGW-BHD/BFS - I think in general the BFS route has more frequency than any other Belfast-London route with many 6x daily days in winter. BHD is 3x daily from this summer.
As to why split operation - the simple answer is it keeps the competition out/at bay. For as long as EZY do BHD to say BRS or LPL then EIR won't and neither will any other random operator. The more complex way of looking at it is the FR effect, it gives EZY another card to play, somewhere to move capacity to and a bargaining chip with BFS.