[Sisom]

I've found the solution, which is quite simple (but you lose the minicart tooltip, which I don't think anybody will use anyway):

Edit customer/minicart_total.tlp

and on line 11 (I think, this may be a few lines out as I've moved things about a bit while working on this), delete the following line:

 
{$lng.lbl_cart_X_items_total|substitute:x:$minicart_total_items:total:$total}

and insert the following instead:

{$minicart_total_items} {$lng.lbl_item}{if $minicart_total_items > 1}s{/if} {$total}

That works fine, as long as you don't need the Minicart mouseover tooltip, because
the label 'lbl_cart_X_items_total' is as follows:

<span class="minicart-items-value">{{x}}</span>&nbsp;<span class="minicart-items-label">item(s)</span>&nbsp;<span class="minicart-items-delim">/</span>&nbsp;<span class="minicart-items-total help-link" onmouseover="javascript: viewTooltip(this, txt_minicart_total_note);">{{total}}</span>

My solution uses the much simpler label 'lbl_item' which is, of course, "item".