Identifying a piece of metal.

Hi everyone.
I hope you will all forgive me for jumping in with a technical question..

I have a 207 1.6 hdi, 2006 with dpf.

Whilst driving I had a momentary hesitation in power, which immediately made me think turbo, so I backed of and slowed right down (fortunately) as I then got a low oil pressure alarm.
I quickly turned into a side turn and shut everything off.

I assumed the oil pickup was clogged as I was on my way home from picking up oil/filters etc as I was going to drop the sump off anyway and inspect.

The engine itself actually made no untoward noises and had been running well returning 60mpg even on mostly short journeys.

I have started the strip down expecting to find a clogged pickup however when removing the oil filter/cooler housing for inspection I found a piece of metal wedged in the non return valve (the valve still functioned but the metal clearly restricted flow) on inspection it seems to be a piece of needle roller bearing race (confirmed be the two intact needles removed from the sump, about 8-10mm wide and about 3mm diameter. The piece of race is too small to accurately gauge the diameter but I expect larger than 50mm.

Everything else in the engine so far hasn't looked too bad. Not much carbon deposit in the oilways I can see and the filter in the turbo oil feed banjo is clean. The turbo has now got some slight play so needs replacing but its far from being a terrible sight.

So question is can anyone suggest where the needle roller bearing thats broken is?
I have yet to remove oil pump as i'm waiting for my timing belt pulley locking pins to arrive but that will be next. Worth a note, the gauze in the pickup was dislodged allowing things to get around it potentially.

Sorry its a long read but appreciate any input.

Thanks