This is my favourite SLS/SLES-free shampoo and I have repurchased it numerous times. My husband has dry scalp issues and whilst this does not cure the flakies, it is much better than other shampoos at not aggravating it (we use various oils massaged into his scalp for that). I wanted to share how I use it because before I was told this, I thought it was pretty mediocre.
The incredibly lovely sales assistant at the Liz Earle store (some of the nicest SAs in London there!) explained to me that you need to double wash with this. I use about three to four pea-sized dollops to massage this into my scalp. I used to have extremely long hair and that was enough because I never really suds up the lengths of my hair with shampoo - only the scalp. Once you've done the first wash and rinsed the shampoo out, do it again with about the same amount of shampoo. This second wash will lather a lot more and feel more satisfying, if you're after the sudsy experience that shampoos with SLS/SLES give (although it really doesn't lather nearly as much as the SLS/SLES shampoos).
If you struggle with tangled hair, I would tackle that with conditioner, rather than trying to use the shampoo to work through the tangles.
I find this shampoo is very good for my scalp - it is not drying and so I do not struggle with my scalp getting oily soon after a wash. It smells delicious and fresh and because I use much less of this than I used to use with SLS/SLES shampoos, that helps mitigate the cost a bit. The price is my only complaint because it's hard to stomach a £8 shampoo! However, until I find something better, I'll be going back for more.