EddThatch

Hi, did anyone get anywhere on this? I have a Vauxhall Crossland X (18 reg) and have had a p0420 code for a while, have had various things replaced including cat converter, sensors, spark plugs etc. Last thing we had done was the cam belt (which I am told is a wet belt) as it needed doing. Since this though the car has been drinking oil, as in a whole tank full in the last 1500 miles. The mechanic has suggested it could be piston rings. Just wondered if anyone managed to get answers? Thanks