The usual half price Persil promotion, but now with £5 for a £20 spend. So get 4 for £15 - £3.75 per bottle when entering code "XXLAX7" at the checkout. Offer ends 7th July.
I always stock up on these offers buying 4 or 8 a time as they usual retail at £10.00. Just stick 'em in the garage or loft if you haven't got the space. It's not as if they go off!