Not long had the Defender fitted with a Disco 200TDi engine. Occasionally on start up there is a tinkling sound and a cloud of blue smoke from the exhaust. After a few seconds, maybe 20 seconds sometimes, the tinkling noise disappears and the blue smoke clears. There is some oil in the intercooler piping but not a great deal. More than a mist coating but not dripping. I am thinking the bearings are on their way out. Anyone agree?

It doesn't happen every time, sort of reminds me of a dry bearing rattle sound till it spins up. Only driven it 75 miles in total and haven't noticed it occurring when mobile. How much play should there be if I test the vanes?

I would say that the turbo is not the problem,
but just to check there should be no more than 0.5mm play in the shaft up and down in the turbo, spin the shaft and wiggle it around if it seems to hit or scrape the sides it is dead, but if not, then it should be ok.
turbos can generally be fine with these engines, mine had done 300 thousand miles, when I swapped it for a newer unit I had laying around, but even so there was plenty of life left in it, and had more oil coming out than you mention on yours.
the obvious is check the oil level, otherwise it could be a leaking exhaust manifold, I've heard exhaust manifolds before that sound like dry scraping, then the exhaust warms up and the noise does away. that's a very unlikely one though.

My 90 also has oil in the intercooler pipework, its nothing to worry about , most small diesels do the same.
On my other tdi I have the engine breather routed to atmosphere and the intercooler pipework is totally dry, so it could be oil mist and not from you turbo.

Blue smoke on start up could also be valve stem seals.
Try accelerating and look for blue smoke once you take your foot off the accelerator that's usually another indication it's the valve stem seals.

As for the tinkling noise I'm not sure I can help.