Simply use the code FDREF58782 in the checkout (expires 15/12/2017 and excludes oversized items).
One use per account (or checkout as guest)
Confirmed that this works on low-cost items and clearance items.
Note: they've recently marked a number of cheaper items from their online store as 'not sold online' so not everything you see on the website can actually be ordered.
Ive noticed the warehouse took away the clearance section on the index. Any way to bring it up through search?
Edit: I think I have found the tab…. oops.