The concept of the cart is that a Sale usually covers a large number of items (e.g. storewide or a complete category) and, if you equate it to a real world shop, it would be more appropriate to announce it either by a statements/banners at the shop entrance, and your visitors would expect to see many reductions.

On the other hand, if you're only want a few items they should be set as Specials where specific attention is drawn to them...you could think of that as the poster in the corner of the shop window!

I would suggest in your case that you show savings as a percentage. Your prices are small and no-one is going to get excited over a saving of 60p!

I'd also suggest that you change your english.php file so that the statement is "Save XX%" which looks and reads considerably better than "Save: x% off"