We still get a lot of these mg/rover vehicles in our workshop due to being an mg/rover dealer years ago.
There was a bulletin years ago on the instrument packs coming up with those `err` fault,the only fix was to fit a new a reprogram a new one in.
As to the `butterfly always open` fault,its the variable valves in the manifold seized up,common fault,sometimes when you force them to work with the scantool the start working again,hard to get ones separate,comes as a complete manifold.it doesn't affect the emissions from experience.
As for the o2 sensor just hook it up to the scope and see whats going on,and carry out a resistance check an the heater circuit.
As for the p1641 check that the ecu isn't full of water as the drain tubes get blocked.
hth lee
