Deal appeared when I logged into my account and added it my basket for the Martlesham Heath store as BOGOF. I bought a lot and they had to substitute for other flavours. I used click and collect to reach a £25 shop which made it click and collect eligible and then used the below code to bring my shop down to £20
There's a code for £5 off £20 of cosmetics and toiletries which is GRKKKP so you can buy some other stuff that you would buy anyway which don't fluctuate in price to get the extra £5 off and make it even cheaper.
Hopefully your local has this deal as it's amazing.
I go through shower gel a lot and usually pay £1 for 250ml in the half price offers so I pay £4 per litre when you calculate it. This real is £1 (or less per litre).