The oily dump valve isn't a problem ... don't worry about that.
The battery? Dunno? Pop the terminals off and put some grease on and
see if it persists. The +ve wire that runs up the inside of the engine
bay to the distribution point on the driver's side bared off on mine
once. It made my radio go on and off oddly and my voltmeter went
scatty. Upon inspection, there were some interesting blue burn marks
on the turbo elbow where it must have been shorting. I was lucky -
check over the wiring and use new P-clips to secure in place.
The deposits on the turbo elbow and exhaust manifold do look
suspicious - you don't have a leak, do you? Check the water cooling
union on the side of the turbo - you have oil and water cooled turbo,
right? My 8V does, so yours should :) If not, see above ...

Best of luck - if it's the battery issue, you need to sort that
quickly. Best pull the negative off overnight, just to be on the safe
side.

Looking again, mate - is your turbo elbow cracked?

Oily ? Where ?

The battery just needs cleaning up as already suggested but likely means
it's on its last legs. A few crystals won't give you a short btw.

As for the white on the manifold, looks normal to me.

Graham