When I activated the OBC in my 2004 Base, I was disappointed with the display and the information available. There are two different cluster/gauges, one has the OBC display, the other does not. I ended up buying a cluster on eBay and reprogramming the mileage to match. Worked great. Then the engine blew, I sold the car with the old cluster. Still have the OBC cluster. My replacement S already had OBC.
I bought the cable pre-made off of UK eBay, much easier.
https://www.ebay.co.uk/itm/175701924469