Pirate,
I have a series 1 and the aircon is good, the car has done 30k and is 10 years old. After a run the cats will smell a bit, but no more than my old Roadster did. I believe removing the cats will activate the engine management light, not sure, but might even trigger the car into safety mode. There was a post on this some time ago.
If I were getting the car sorted I would head to Richard Thorne, Reading area, they service and work on many series 1 vehicles and they know what they are doing.
