Peugeot 306 2.0 HDi - Cranks fine but won't start - SBK

Hi all,

I have this 306 which, suddenly, refuses to start. I was messing with fuses chasing another fault so a bad connection is possible/likely. Next time, it was very hesitant to start, later, no fire at all. Was seeing 3v on the (disconnected)stop valve connector which is very suspect. Any tips welcome.