Thanks for the info, but I don't have a smart phoneThe car’s own regen capabilities are very good. If you have an Android smartphone, the “VAG DPF” app can be a very useful tool to monitor the health of the DPF. (Coupled with a suitable Bluetooth transmitter to plug into the car’s OBD-II diagnostic port. Such as an ELM 327 transmitter). VAG DPF reveals that when the DPF’s soot load gets over around 80% then a regen is triggered when other conditions are met, such as a decent journey length seems to be underway, oil and coolant temperatures are fully up to normal, exhaust temperatures adequate, no other fault codes present, etc.
Once a regen has started the ECU injects extra fuel during each cylinder’s exhaust stroke, to raise the exhaust temperature to well over 600 deg.C. When soot burn off can take place. It can take as little as 10 miles of main A-road driving to complete, bringing the soot load back down below 20% again. Provided there are no stops or traffic lights, etc. along the way. That would allow the exhaust temp to fall and interrupt the regen.
So 10 miles outbound to get everything up to full normal temperature and enable the regen to start, then 10 miles back to let it complete, can be enough. The advantage of using VAG DPF to monitor, is that you can tell exactly when the engine is ready to start a regen and how it is progressing.