It might be worth trying a 'Hard Reset' - I think the flashing you mention apparently tells you any four digit fault codes ie 10 flashes = 0, and 1-9=1-9.So, on this ECU reset - I tried it and what I got was the flashing ECU symbol on the dash.... quick quick quick, then slow slow slow.
No idea what that means or how long you're supposed to leave it for. Might help if I had a Workshop Manual!
As far as these relays go, what's the difference between the black ones and the blue ones? What do they do?
Also, if you open the relay box, it gives you a brief description inside the lid of what each relay does - but I don't remember it being much more that '4WD Trans System' or something similar.
These relays are only around £20 each direct from my dealer and to date has solved my problem completely. I found this out from Blackshaws Nissan in Alnwick are a family dealership who unbelievably honest, non rip-off and expert in practical D40 know-how (believe it or not!).