Hi all. 
 

I’ve yet to see it mentioned but my 2016 Octavia VRS estate had a leak from the connector port on top of the coolant reservoir. 
 

If I  moved the connector plug back and forward you could hear the high pressure leak. 
 

this was getting the plug wet and I am sure would have led to electrical issues longer term. 
 

hope this might help someone else. 
 

pretty simple job to do with some hose clamps. 

Yes it is very simple to change WHEN COLD! Make sure you use G12Evo coolant. A nasty side effect of this is water can be forced into the wires and travel all along them to the next plug/socket and cause a lot of damage.