Thanks for your reply Gert - no, I've not tried using anything yet.
Yup, I can grind down the RHS bolt so it actually tightens, but more of an issue is the 10-12mm or so spacer that I may need, and then a longer bolt.
However, it does seem to me that these are not made to fit the bike. I'll wait and see if I get a reply from the blokes that sold them before I name them with either a positive solution or a slagging off !