Car will start fine 49 out of 50 times but without obvious reason it sometimes struggles to start (as seen in video). This can be on a cold start or a warm start. Happens in warm, cold, wet and dry weather.
Bought the car a month ago - full service history - local mechanic gave it the once over (after we noticed this issue) and said that everything looks good.
It has had a new battery (installed after the original one failed a week after purchase) so I doubt this is the issue.
It has been plugged into two separate garage's computers for diagnostic with no errors recorded. Two garages could not find a fault (they didn't witness the starting problem - I have only just managed to capture it on video). Any ideas?