Had a good day doing some jobs on the zed today, one of those being new oil, filter and replacement of the oil pressure sensor. I noticed the original one was not screwed fully in but assumed that was how it should be. Took it out and found that there was a small bit of gasket seal stuck on the face of the sensor which must have been causing the original problem. Replaced it anyway and screwed it in until it got tight which was about half way in again. Filled up with oil checked for leaks all was ok, took it for a drive checked again all was ok.
Anyway thought about it for a few hours and thought should it be tightened all the way in, checked some pictures online and they looked like it was fitted flush. Have a made a boob and should it be all the way in?
Here is a pic of the old sensor showing how far it was screwed in, which is about the same distance as the new one went in.