Can you supply a bit more detail on what happened originally, and exactly what part you have replaced each time?

Škoda replaced it the first time it went under warranty.  That one lasted about 6 years. When it failed I got one of eBay made by DPA. I replaced it my self but it only lasted 3 months they reluctantly sent out a replacement and that lasted 12 months   The problem is the same each time as the cable becomes tangled on the circular guide and jams. As on picture. I’m just thinking that the old adage is correct buy cheap buy twice. Both the Skoda ones failed due to the cable rusting through. Cheers. 

Each time the complete window regulator was replaced but not the motor. 

What year is your car and model

That looks like rust deposits which suggests water ingress 
 

Hi. It’s a superb estate 2010. 2ltr diesel. Rust was the cause of the first 2 units to fail but it looks as if the cable has slipped of the guide and been chewed up. There is only one way to install the regulator but I was wondering if I had missed anything on installation or if any one else has had problems with cheap regulators. Thanks 

Perhaps the answer is to cover the new cable in a very thick grease to prevent rusting?