That is weird, which replacement bushes are you fitting and who is fitting them?
You should only be fitting the revised "3 arm" or is it "2 arm" genuine VW Group parts, and getting them fitted in the correct orientation.
If that is not working for you, consider buying Cupra version which are solid, so should last a lot longer, I got the original "4 arm" versions replaced in my wife's previous 2002 Polo when the car was roughly 5 years old, by that time only one side was starting to tear, I got a good VAG Indie to fit Cupra equivalent parts which were still as good as new when that car was sold at 105K and 13 years, with the bonus of improved feel to the steering, that car was a 1.4 16V 75PS one, some TDI engined car can become a bit too "rough" if fitted with Cupra solid bushes.
