I can only get this on first start up ,after changing gears i never see it again all day ???any ideas

It's just a small metal contact on the end of the selector drum. If it gets gummed up, or the spring in the switch goes, then bye-bye neutral light. It's an engine strip (including splitting crankcases) to fix. No idea why it would only show after starting and then never again.

thanks that will be staying as is then

Mine is exactly the same. Theres the odd time when idlin, if you tickle the gear peg with your foot, you'll sometimes get the odd flicker of green... then nothin