Hi....welcome to the Forum
There are several things that are necessary for a DPF to regenerate and operate efficiently.
Firstly, it needs to be driven correctly, which if you do 500 miles per week, I imagine that it is on motorways and other major A roads, in which case the average speed would be around 50 - 70 miles per hour.
This is fine for a regen and should keep the engine and exhaust system emissions clean.
Also, the correct engine oil should be used (low ash content) and also good quality fuel is good to use.
So it looks like your car is regenning as it should now
Cheers, Trevor