So will he be saying goodbye to Luton or could Luton handle one?
No - LTN cannot accommodate an Airbus A380 as the surface infrastructure - runway width (no hard shoulders), turn-offs and taxiways are not compatible with the A380's requirements. Neither are any parking stands.
So unless the aircraft's owner is willing to pay for the additional concrete (LLAO certainly won't...) he will not be operating it through LTN.
But... given the fact that many 'lesser' airports world-wide (i.e. not just in the UK) cannot accommodate the A380, why would he dispose of his Boeing 767 which offers significantly more flexibility in terms of where it can operate?