Crankshaft sensor code

Hi all
Had a strange problem develop over the last two months.

When cold, engine will turn and then die just before it fires up. Always fires up second time I try to turn it on.
When hot (or even just after that first start), fires up immediately every time - no issue.

Scanned with INPA and PA soft - both reported crankshaft sensor. Got OEM and replaced (measured etc)

Same problem after changing. So now I'm not sure if it's even the crankshaft sensor any more. I can hear the fuel pump priming in POS II..

Anyone seen anything like this before?

S62 engine // 99 build year E39