Vauxhall Meriva no dash lights but engine is cranking fine but no start

Try banging instrument cluster / dash panel with heel of your hand . If that works , pull dash panel and check plug / connection on panel

Did not work giving a bash ....left overnight lights on to let it start drive 100 yards cuts out with lights again

Check all battery terminals and earths ,especially from engine to body . Check all fuses .

Already checked battery terminals and earth as I say good cranking so earth ok checked all the mega fuses cos easy access but to get to main fuse board its major surgery under near side wiper. It's the intermittent on off that is getting me thinking about the ecu or another sensor

Check this on vauxhalls with this fault ,

https://www.vauxhallownersnetwork.co.uk/threads/no-dash-lights-engine-wont-start-fixed.435779/page-3