M&S has a code that takes £5 off £30 / £10 off £50 Spend on lingerie at the moment (BRAFIT), in itself it's not exceptional, but on 3 for 2 or buy 1 Get 1 Half Price lingerie offers it's taking the discount off the Subtotal price before the offer discounts are applied.
So, I added 6 x £6 pairs of knickers, total £36, added code BRAFIT, took it to £31, then the 3 for 2 offer kicked in & it took the basket down to £20.66.
Tested on 9 pairs of £6 knickers, total £54, added code, took the baskey to £44, then 3 for 2 offer kicked in & took the basket to £29.33,
Even better savings can be had on the Buy 1 Get 1 Half Price Cami / Vest tops they have on ie; I added 10 x £6 Vest Tops, total £60, added code, took it to £50, offer kicked in taking the basket to £37.50.
Another example; add 6 x £5 Vest tops, total £30, add code, basket now £25, offer kicks in taking basket to £18.76.
Only a few pounds saved & only really worth it if you want to but multiples of knickers / vest tops or are after M&S lingerie anyway, but thought it worth sharing