It was being looked at in DUB and the conclusion was that airports with a strong based airlines it puts them at an operational disadvantage as they have no choice but to pay the peak fees as aircraft on the ground don't make money and delaying morning departures reduces aircraft production where as carriers flying into the airport could adjust schedules to cut costs. The UK/Irish time zone has an affect on peak capacity as flights must depart much earlier to make it to key business cities by 9 or 10 in morning where as inbound flights can depart much lather therefor spreading peak operations at mainline Europe airports. The last thing was as based carriers contribute pay huge % of airport charges any shift to off peak times could result in overall charges going up for everybody.
While DUB is no where near LGW plans for peak charges have more less being scrapped as for once the DAA, EI and FR all agree it's not the answer to the problem.