yep sounds reasonable to be some sort of blockage?
id want to remove feed pipe from blck and see oil flowing out with cranking, then a pressure gauge in block maybe also?
in the feed pipe connection in the block there should be a fine mesh filter, if your not renewing it you want to remove and carb clean/ultrasonic clean the filter and pipe thoroughly and the same for the drain pipe to sump.
was it a garage that fitted the new turbo? most will want to confirm oil flow as they will have to warrant turbo.
the diagnosis contaminated oil?
what is contamination high diesel contant?high soot content?
I cant see contaminated oil killing a turbo in just 10miles?
has turbo been inspected? what has failed broken shaft/worn shaft ,worn bearing etc?
I did turbo swap but it was before old one failed as such so I had no fear of blockages but checked anyway.
this was mine after I did an oil flush to start before removing the old turbo , oil drained turbo removed and renewed oil and filter with new oil(asda cheap but correct spec and fully synthetic)
then I disconnected injectors to save it firing up and cranked over to confirm oil flowing from block, you can still make out a bit of crap in the oil as it runs down block.
turbo refitting march 2012 017 - YouTube
when this eventually came clean(only cranked for second or 2 at a time )I carried on and fitted turbo
I had already primed the turbo bearing with oiland pre filled the clean and free flowing feed pipe and banjo
this is screen in feed banjo(you can see how fine mesh is zoom pic )
then turbo fitted and cranked again to see oil dripping from drain flange
then drain pipe fitted
oil refilled to correct level
then vnt vac hose disconnected(to give min spool low boost)
injectors reconnected and fired up to idle
left to idle to test for leaks etc
test drove with vnt hose still disconnected
vnt reconnected and driven gently for 50-100 miles to let turbo bed in(keeping foot off to keep boost low/mid as I could watch on boost gauge)
then when happy all o.k and normal given the beans
after a few thousand miles I drained cheap oil out and replaced with new filter again
ps im not a mechanic might not be the correct way to do it?