Ducati Sporting Club UK - Oil gallery bolt problems anyone??

My bike engineer is Ducati John at Stourton, Leeds (he is a first class engineer on all fronts if you're looking for one). On a large service, he's found some alloy swarf in my oil strainer. With the rear barrel off, the culprit appears to be the oil gallery bolt.
This screws into the crank and creates the oil pressure needed for the big ends.

Apparently, it's not that uncommon for these to start unscrewing themselves. They then get rubbed away on a steel ring on the inside of the left hand crank case. (The early engines had alloy gallery bolts - they were steel on later models).
If it totally gets ground away, there will be a sudden and complete loss of oil pressure.

To replace this ten bob part, it's the engine out and a total strip-down to the crank. And is it not possible to tell how much of the bolt has gone without this strip down.
From the amount of swarf, I've decided that I will live with mine for now and check the amount of swarf at the next oil change.

Has any of you had any experience of this problem, or do you know more detail on it than me?

Any ideas will be gratefully mulled-over.

Mike Chadwick