Vauxhall Insignia vauxhall insignia 09 1.8 engine rattle on start up or left for a bit

With that year and dependant on mileage , could be general engine wear . You could try changing engine oil and filter , using a good , correct oil .Might help .

It’s had new cam belt new vvt and sensors new Vauxhall oil and filter someone said there is a update on the ecu

It’s 09

If not engine wear due to high mileage etc . might be oil pump / pick up . You could also check for low oil pressure with a master gauge .

There is a common fault with some Insignias with the rubber seal on the oil pump pick up pipe which goes hard and causes reduced oil flow.