The Sun manages to hedge its bets:
"Incredibly, the captain still managed to land the Boeing 777-300 without a problem and there were no injuries"
followed by
"Flight AC864 an A330 with 294 passengers on board landed normally in London and taxied to the gate"
Judging by the photos it was the right front wheel on the RH MLG - interesting that it appears to have managed to taxy from a 27R exit all the way back to T2 without ATC noticing anything amiss.