The Emirates A343 models are being retired - Two already left fleet.
They are F12 C42 Y213 - Premium heavy compared to the 77W
They normally use a high density 77W either C42 Y386 or C42 Y400 to Birmingham
Some mid week flights employ a mid density with F8 C42 Y310 in which case the F8 are blocked.
The 77W also has increased pallet space.