Whats that.....about a 30 minute flight??? Plus 3 hours to board and 3 hours to disembark at the other end and claim your luggage...........
Didn't take that long when EI used 747's and 330's for a few rotations over the Christmas period DUB - LHR. Depends on how much the operator is prepared to pay for handling, if they are a cheap skate operator, and go for low cost handling, that's what they will get, if they pay for a full crew and the equipment, then it happens a lot more rapidly.
Matters not if it's a 747, 767, 777, A300, A330, A340 or A380. You can add DC10's MD11's and any other bin loaded wide body you like to the list.