Ignore 0420/30 for now. That's sensor 2.
You need to fix sensor 1.
There are no cats between the engine and sensor 1. So sensor 1 is purely concerned with exhaust gas created by the fuel/air mix. It's reporting the fuel air mix incorrectly, so the ecu is trying to "trim" the mixture by adding or subtracting a % to the normal injector timing duration. So your getting a fuel trim code as well.
Sensor 2 is AFTER the much smaller pre cat. So it's expecting to see some cleaner gasses (pre cats are there related to cold starting emissions in the States I think. Whatever, it was a crisp idea.) But because the PRE cats are old/small/have an exceptionally hard life the catalyst wears and becomes inefficient, as the codes says. Moving sensor 2 to a location AFTER THE MAIN cat, restores the efficiency sensor 2 expects to see. So 0420/30 codes disappear, the light stays off, and you can then see when the light comes on for a "genuine" fault, like a dodgy O2 sensor or a misfire etc....