A lot of the reviews that mentioned the clamp said it was impossible to tighten it sufficiently to hold the guard in place and that subsequently it swings around the seatpost very readily.
Thanks. That does sound much use then. I wonder if it could be solved with a small piece of rubber under the strap. It's a shame as the 'guard seems pretty decent in all other respects.
A lot of the reviews that mentioned the clamp said it was impossible to tighten it sufficiently to hold the guard in place and that subsequently it swings around the seatpost very readily.