I was the first person than crawled into the back of one those engines that was shutdown inflight and I can assure you that there was a severe fuel leak from a high pressure fuel line onto and around the combustion chamber case of the aforementoned #3 engine.
You guys are just lucky that Jet A1 isn't easy to ignite. That engine was soaked in fuel on landing, even after an inflight shutdown.
I can assure you that one of the pilots could have seen fuel streaming from one of the engines if they had been alerted by a passenger and gone and had a look from inside the cabin(which is probably what happened). From memory 2000kg/hr.