Doggo wrote:

Yep, wasn't the greatest discovery.
It's absolutely FUBAR that it's happened tbh, most ridiculous thing ever!
I knew I'd dropped the old oil pressure switch when I removed it, but it was late at night and the car was on the trailer at the time (so I couldn't get underneath it and there were all sorts of places it could have dropped and disappeared!) so after about ten mins looking, I gave up. For all I know now, it had landed up top of the driveshaft, under the sub-frame, meaning there's pretty much no way I would have seen it, even if I could have got under the car!
It then ended up being over a month before it was moved off the trailer so by then I'd forgotten about it
The fact that today it got wedged between the driveshaft and the sump and then that the rotating drive-shaft forced it into (and through!) the back of the sump is the most immense bad luck going, though!
Fortunately if you're gonna hole the sump, it's the best place to do it though
It's below the big ends and above the sump baffle plate, so doesn't sound like any damage done and hopefully I've got away with it (engine still runs perfectly, which is important for a big hydrualic citroen, otherwise you just have a beached whale on your hands!).
So just massive aggro (and means oil leak when the engine is running!). I need to get the ramp installed and get my hands on a replacement sump before I can fix it...
If it had got in and mangled the big ends, it would have made the future of the car pretty easy to determine...