OK, I sorted this myself quite simply.
Basically, I wanted to have two separate links in the left hand side category menu pointing to only one category.
I did this by editing skin1/customer/categories.tpl and put an if statement in to read:
Code:
{if $categories[cat_num].categoryid eq 3}
<FONT class="CategoriesList"><A href="home.php?cat=5" class="VertMenuItems">Shoes</A></FONT>
{/if}
In this example I'm hardcoding the link to the "Shoes" category so that it points to category 5 (which is the existing category of "Shoes and Trainers", hence the need to have two links to it in the menu). The link appears after category 3 is displayed.
Although this is a low level manual hack it does the job!
Dan