Instructions:At the checkout, simply write the following combination of codes:
This gives free delivery, 20% off, and 10% off! - overall 28% off plus free delivery.
When you consider there is a Blue Cross sale on at the moment, this becomes pretty ridiculous.
I found this by chance a month or so ago - I entered the wrong 20% off code at checkout and this one worked. Sorry for not posting earlier - I assumed it was already on the forum until I saw the Blue Cross sale link last night.
Hope that helps!