Erm, it seemed the site had gone a little haywire. As far as I can tell, automated listing updates from my order processing system were creating additional sections and listings in rather random places. Anyway, hopefully, I have now got all the products listed under the right headings with the correct stock quantities.
You'll notice that there are now sub-sections under main headings. So, for example, rope is now divided into the various sub-types. I have also updated an error message which unhelpfully tells you that you are not authorised to view a page to add that you might need to be logged in.
Please let me know if you notice any errors, peculiarities or just things that could be improved. It seems that changes are even easier than I realised with their live on-screen editor so do let me have your feedback.