There is a link back to the home page and all other major pages on every page on my site. No page is more than two clicks away from any other page on the entire site. So it's not a navigation issue.
What I was doing was adding a text link within the article on some major keywords back to the home page, where all the products are listed. Only one or two links per article, and not on all the articles. Some have natural links to the product, where the topic of the product is mentioned - even vaguely.
Now I realise that linking to the home page from within the article itself isn't such a good idea thanks to the contributers to this thread. I am going to start adding tag lines with links to the product pages - for those article which I cannot alter to incorporate a link within it.
Thanks for your replies.