Slight coolant leak - drips on ground

Hi all,

I have noticed that our 2007 Auris 1.6 has a very slight coolant leak.  After many hours of the car sitting still, i.e. overnight, there will be a couple of drips of coolant on the floor. around the offside area of the engine.  I know it's coolant because I put some cardboard under the car to try and see if the oil was leaking (trying to diagnose excess consumption), so I wasn't expecting to see coolant..!

Are there any common leak points on these?  I have been under the car and thoroughly poking around and cannot detect anything.   I guess the next step is some UV dye.

Thanks.