Hi again.
I've just read the "mud- club" link, and I've had a very similar incident with a set of ROUGH-RIDER tyres. I'd had a rear tyre go flat, and when I got it off i did the usual, looking for the offending screw, no screw But i had noticed that the 10mth old tyre was split, almost half the "circumfrence" of the tyre, right through the thread and down to the wire, so I checked the others and then noticed that the side walls were starting to split.
I contacted BRONCOS sent them photos and they said it was accidental damage, the sidewall splits are Ok as they're just a venir, "as from Feb I belive the law want to hand out 6 points per tyre for damaged tyres..."
In Bronco's defense they did offer me a new Tyre at trade price..