Sounds like bad luck George,
It is critical how you mount the black iron bracket as to wether it clears the tyre properly on the chain side.
I had to undo mine and refit it to make it clear properly but it was easy and no big deal.
Sounds like yours was made incorrectly with the mould though.
Iceman has one too and so do a few others here and no probs that I have heard of before.
Davem