Hi Shirt
On cars with the particulate filters it needs to regenerate it self from time to time. So a lot of town/short distance driving doesn't really help this filters either.
When the car wants you to help it regenerate itself the yellow warning light will come on and you would have to drive the car on the open road for a period of time 20min-30min at about 2000rpm. Normally if the regeneration proses was success full the light will stay out on the next starting cycle.
If the car cant manage to regenerate itself for some reason the engine warning light will come on and the particulate filter light will turn red. Then you need the workshop.
When you ignore the yellow light and keep on driving until the red light come on then regeneration of the particulate filter might not happen on the open road. And if you keep on driving with the red light on and not consulting the workshop then you will end up with the power loss in your case.
VW in such a case does not pay for an particulate filter , its the owner's problem
D