This was one of the 10% ... it was an engine issue.
When they turned back over the midlands they were reporting it as a minor issue and wanted to descend but did not want to declare an emergency.
A while later, somewhere to the NW of London they upgraded to a 'Mayday' call and were given a 7700 squawk; they said that wanted to land at Heathrow and would require assistance upon landing as they had shut down an engine.
Somewhere to the SW of Heathrow, and still at FL180 they asked about dumping fuel. I never heard the outcome of that, but they did continue until over the Channel, where they may have done so.
Once over the Channel they continued south and eventually landed at Paris/CDG.
As all ended well (none of this 'bravely avoided landing on a school' tosh!) it is a 'non-story'.