Apologies if this turns out to be a non-event, but my curiosity was raised by the fact that it carried out a pretty much straight in approach after it turned back (would there be issues about an overweight landing or would it have burnt off enough fuel) pitched against the fact that landing on 27R at LHR meant it overflew central London (which would suggest whatever was wrong was minor).
Several tyres deflated after landing and taxiing off of the runway so I can only assume it was overweight on landing and had very high brake temps.
Anyone heard why it turned round?