Yellow oil light flashing 5 times

[Euler2]

I have a 2003 9N AMF TDI, as described the yellow lamp flashes 5 times on start up.
I have checked oil levels and are good, changed the oil pressure switch, and changed and tested the bonnet latch with a new micro switch ( hard to get hold of).
This car was not designed with the oil level/temp sensor on the sump, but my cheap code reader tells my fault code 00562 and G266 ( the oil level sensor ).
How do I proceed to get rid of this annoying problem. Anyone still out there with any clues.
I've also seen it says should be set to Fixed Servivce Interval and not Long Life.