Despite the applying reward points to sales items issues (where it halves the value of them) they work at full discount price for non-sale items. Arrow are also doubling all reward points for anything purchased during the sale period.
With that in mind, I ordered:
Blind Woman's Curse
The Killers
The Long Goodbye
Super Bitch
Total = £28.96
I received 579 reward points for the order, which I've just used in conjunction with the 248 reward points I already had to pre-order Nekromantik, which only cost £10.72.