I have had an email this morning saying they're selling pre-cleanse at £10 off until Friday.
I recall an offer last week too and possibly the week before so it may be worth signing up for their email of you usually buy Dermalogica stuff.
I like and use pre-cleanse so am thinking of stocking up while it's on offer but hoping for another offer next week on something I use a lot
No code required from what I can see.