Mk4 1.25 zetec engine turning over not firing

[Teenz]

Hi, just been given a 1999 fiesta that has been off the road for over 4yrs. 
it’s only done 65k and was running perfectly before being laid up. 

The problem I’m having is, the engine turns over but is not firing.
Fuel gauge is reading 3/4 , a good £11 of that fuel is fresh.

The fuses under the bonnet have been checked and we have swapped a relay around.  What is the black diod? Fuse for ?, after swapping the relay, the engine was turned over and we got a bit of a fuel smell but I’m sure I can’t hear the pump priming, even with the Back seat lifted. 
no faults are coming up on the OBD reader. no engine management lights are coming up. 
everything electrical works, it’s just this issue.
any ideas ? 
 

thanks