Welcome to the site Geoff
Any auto is going to be a bit slow until it comes up to temp. What you're looking for is rough changes &/or rough changing into Drive or Reverse from Neutral when it's at normal operating temp.
As for it not starting first time - could be a number of things - I'll leave that to the more mechanically minded to give a list of things to check.
Squeaks and Rattles - welcome to Vectra ownership - someone might have had the dash or interior panels off in the past and havent put them back on properly or tight.