I mentioned this in another thread the other night Ian and I was told off and given lines .................I heard two guys talking about this when we were out last Sunday - they were obviously plane buffs. Said they'd heard that metal swarf had been found in the oil during a service on one of the planes.
The BBC pointed the problem at the pinion gear on the final propellor drive.
http://www.bbc.co.uk/news/uk-england-lincolnshire-41095753
Tony.