It's a pity that it's raining. Otherwise, I'd take some pictures of the tyres so you could see the extent of the problem. And now for a diversion.....
When I bought my 25. It came without the normal information that goes with these cars (Unlike my old 400 which came with everything). I got the Handbook and a single key with its fob. That's it! Of course, this meant that I needed the EKA code (A new key can come later). I have to give mgrovercodes two thumbs up for their service. I think that £20 is a fair price for the code. After I received it, I went out and tested it. It worked!
Now. There appears to be some variation in the instructions and consequences in entering the code. I used the instructions provided by mgrovercodes and they're more accurate than the instructions in the Rover 25 Handbook. However, there were some differences in what happened when I entered the code.
The first step was to put the key into the drivers door and turn it clockwise and hold it there for 5 seconds. Then return the key to the central position.
The second step was to turn the key anti-clockwise for the number of the first code digit. What I wasn't expecting was the alarm to sound. When the key was returned to the central position. The alarm stopped. The entry for the 2nd, 3rd and 4th occurred as per the instructions. Once finished, the horn sounded to indicate a successful code entry (Again, not mentioned in the mgrovercodes instructions). I could then open the door by turning the key to the unlock position.
The mgrovercodes instructions mentions that the indicator light would stop flashing upon a successful code entry. It didn't. It kept flashing. It didn't stop flashing until I had put the key into the ignition and turned it. The light went off and the engine fired right up (Boy. Did the Handbook get that one wrong!).
I even tested the whole thing by locking the car with the key and restarting the car. The immobiliser was well and truely deactivated. Normality was resumed when the plip was used again.
I reckon that there are some variations in the SCU's. This would account for the discrepancies in the instructions for using the EKA code. I'm not all that worried though. I've got a working EKA code and that's all that matters.