During a trip after stopping for a coffee or a chat, when trying to restart the engine the ignition works starter motor turns but engine wont fire even though there is plenty of juice. Leave it for 5 and then starts fine!! Got a service, new battery and alternator 3 months ago.
Any ideas what to check?

It could be the crank position sensor. With no signal from that sensor the engine will turn but no spark will be generated, which of course means the car will not start.

Sounds like u might have a ''hot'' start problem. This could be the coolant temperature sensor is not working correctly. If the car thinks the coolant is cold it puts in a lot more gas to help it warm up. Too much for a starting event if the engine is warm. You might also notice really low gas mileage if this is the case. Another possibility is an air leak on the manifold or something when it is hot. Then when the car cools enough & the metal contracts, it closes up the air leak.

l would start with just changing the coolant temperature sensor, they r not that much. And a quick spray of starter fluid to look for leaks would not hurt either. l am assuming the car has fresh spark plugs & fuel filter from the service.