She lives, got her going this morning, this was going to be my last effort before setting fire to it or taking it to a garage. So what did I do, well basically started from scratch, I flushed the fuel system out again, checked that fuel was getting to all parts, put in a diesel cleaner, supposed to get rid of water and stuff, checked all connections and put it back very carefully, checking as I went.
Now here is the strange thing, I hooked up my laptop just to check the errors, still there, so I decided to clear them, recently the P0090 has stayed but this time it went off. Started to crank the engine, nothing, bit more cranking and it fired, took a while, then it started. Yeah. Happy days, just finished putting it back together, going for fuel as it is now sucking fumes as I managed to dump a load on the floor and it only had a gallon I it to start with. Sooooo, here's hoping all is well. One thing, at the moment it is a bit smokey, hoping it's just residual fuel etc.
Oh, the other thing I did was to remove all the earthing straps and give them a good clean, they all seemed OK but you never know.