Diesels in town are poop, get a Petrol.
DPF Regen, typically, take 20 mins with the car (already warm) running at approx. 2000rpm - this raises the exhaust temps enough for the sensor to tell the DPF to start a regen cycle.
After market additives are shiv, use them to prevent a problem but not cure - it doesn't work. Use decent fuel with additives in, it's a false economy using poor quality fuel.
Diesels are more expensive to run = bollix. They only become expensive when they are used as run arounds. A diesel that only covers 6K a year on a motorway will be cost benefical vs a petrol doing the same (with today's technology), change that 6K to town and it's a different matter.
YOU DO NOT USE MORE OIL in a diesel when on the motorway than a petrol does, in fact you shouldn't be using any, if your are you have a leak. If anything oil level will INCREASE in the sump due to failed DPF regen cycles.
I am in the business.
edit to add
removing a DPF is one thing to do, but needs doing properly as the ECU will need a remap and the sensor adjusting as it will freqk the ECU out.
Removing the DPF IS illegal for road going vehicles. If someone says otherwise, then please ask them to confirm what planet they are on.