So this morning I drained the oil and put 4l back in (sorry, I don't buy the stuff about not using drained oil if it's new enough - other people have other opinions but there's no point arguing over it

). I've left it on the flat so I can check when the new dipstick arrives.
I took the bottom off the intercooler. This was the oil in the bottom:

I checked the mileage and I've actually done about 800 miles since flushing it. Hard to say how much of that is newly arrived in the air intake, and how much might have still been in the intercooler or pipe from the turbo after I flushed it. I cleaned this out, blasted the heat exchanger through with some compressed air, but decided against flushing it thoroughly again at this point (incidentally, I tend to use brake cleaner for this sort of thing - it evaporates much more fully and I don't fancy petrol hanging about it in the intercooler. Though as Gibbo says, petrol as a workshop solvent isn't a great idea. I sometimes use diesel instead, but it's pretty nasty).
I also cleaned out the pipe from the turbo with paper towel. There didn't seem to be much oil in there, but I noticed the u-shaped section on it, which sits downward and is presumably to catch oil/other contamination. Flushed it with a bit of brake cleaner, but still not much obvious oil.
So to the turbo itself
On closer inspection, it does seem there's not insignificant play in the bearings
I managed to take this video with my phone as I moved the end of the impellor shaft with a scriber:
https://www.dropbox.com/s/p5zhkh8kqk092 ... 6.mp4?dl=0
Tell me if you think that's normal but I think that's too much play for something doing at least 25kprm.
I'm guessing given this engine's reputation, buying a used turbo is a waste of time and money. Any recommendations for an aftermarket turbo? (Or go on, entertain me, how much is a genuine replacement turbo from Citroen?

) I'm quite happy to by a replacement core and rebuild it, as long as the replacement core is good quality. Again, recommendations appreciated.
The mystery then, is how it's ended up like this. The turbo was replaced at Citroen dealer in April 2012 at 57k miles (i.e. 6 years and 45k miles ago). At the same time, the engine was "double flushed" and the sump, oil pickup and pipes replaced (at a total cost of £2220 - yes there are four numbers there

). Is it normal for a turbo to wear out after this time/mileage? I know turbo failure is common on these, but there's no evidence of excessive carbon in the oil, in the sump, pickups, turbo oil feed, strainer (it's got the new style higher flow strainer in the turbo oil feed banjo bolt, probably replaced in 2012). How long should a turbo last?