For example, when I need to fly to TPA, I fly into LGW the evening before, straight to hotel and depart the next morning, with no travel round the M25. On the inbound sector, even better. Arrive from TPA about 9:00 a.m. and catch the EZY flight to MJV 3 hours later.
I would be worried about EZY cancellations and all the dramas associated with that. Now BA and IB are one so to speak surely going via MAD would be a better alternative for you?
If you live 'North of the Thames' then many people still find travelling to LGW quite daunting in this day and age. Therefore I guess many would not want to see their destinations transferred from LHR. Living in BHX I would be allowing 5-6 hours to get to LGW. Not a pleasant thought.