Both front windows are intermittently working,  fuses OK, cant find any loose or broken wires.

 

Any history with this?

Where have you looked for broken wires ?

I've looked in the door gap and under the dash

Have you pulled the rubber boot back both ends to check at the door / A pillar,

 

its is highly likely thats where a broken wire is.

So the windows both operate after I disconnect the battery and leave it for 30 mins or so.  They also operate on the door key for open/close.   So a broken wire is pretty much ruled out.  I think it's starting to focus in on the regulator controller??

You stated intermittent fault so that still does not rule out broken wires as they start to snap but still make contact sometimes, other times not! I would look real close and even wiggle them to check, right inside the gaiters, both sides and all along the wires. Any sign of fracture, breakage is a good clue as it is, simply, the most likely issue with windows and mirrors!

We get this on our Fabia on occasions. It's very strange. It can go months without fault and then all of a sudden one window (usually front passenger but can be rear) stops working.

 

The fix for us is to lower all windows down with the key fob (global opening) and then roll them all back up again with the key fob.

 

This will then fix it for months.....strange!

 

 

On 15/01/2020 at 11:45, Plantman said:

We get this on our Fabia on occasions. It's very strange. It can go months without fault and then all of a sudden one window (usually front passenger but can be rear) stops working.

 

The fix for us is to lower all windows down with the key fob (global opening) and then roll them all back up again with the key fob.

 

This will then fix it for months.....strange!

 

 

Yep, this exact issue happens to me! 
Key unlock button hold then lock button hold resets something. Found out from Silbury Skoda a few years ago but can’t remember.

we have had this many times and it was broken wiring inside the driver door. The protective sheath (forget name- apologies) basically pulls on cables each time driver door opens and loosens them. We had it fixed twice with new wires now. Apparently a design flaw !