I've done a quick search and couldn't find anything that would help me with the following:

 

When locking the car with the remote all doors and boot lock fine no problems at all there.

 

But, when I unlock the car with the remote just the drivers door unlocks, I try and press the unlock button twice but nothing happens (even tried constantly pressing it). If I open the drivers door and press the unlock switch on the drivers door all doors and boot open.

 

Is there a setting that stops the remote from unlocking all doors, or has something gone wrong?

Could be corrosion at the main connector inside the door due to water. Connector is mounted near the window lift motor. Many pictures recently on this forum

Could be corrosion at the main connector inside the door due to water. Connector is mounted near the window lift motor. Many pictures recently on this forum

 

Is it easy to replace? Any idea on cost of new part?

Is it easy to replace? Any idea on cost of new part?

They're expensive, circa 100, but if you get into it you may find a broken or corroded pin which you may be able to solder something in place of. Or you may be lucky and you may be able to just clean it up. Would definitely try a check and clean first. There's a thread in tech section.

And while you're checking that have a look at the loom too.

Is it easy to replace? Any idea on cost of new part?

 

If you are lucky, you can just clean both parts of the connector with switch cleaner. I did this and found that one of the corroded pins fell off during cleaning. The Skoda garage quoted £400 for parts but not sure they knew as they called it a window lift motor. [The fixed part of the connector is on a printed circuit board mounted in the control box near the motor].

 

In my case I managed to fabricate  a new pin and fix it in the pc board. Check especially the lowest pin in the middle row as this has 12 V on it most of the time and corrodes first.

 

Many posts on here with photos, including how to use silicone grease for protection and making an umbrella to divert water.

 

When unplugging the connector, you lift the bar at the top which locks the parts together. During the last part of the movement the bar will start to move out with the connector so you then don't need much effort to pull the plug off. If it won't separate then you did not pull the bar up enough.

 

Take a look at the many photos and all will be clear. 

Cheers guys, sounds like a Saturday day off kinda job to do.