Geographic variations in coconut milk
If you examine the ingredients on different brands of tinned coconut milk you can find percentages of coconut ranging (and I used the Tesco Supermarket website to get a sampling as they always list product ingredients) from 25% up to 72% and possibly higher. There will also be varying proportions of water, thickeners and emulsifiers such as Guar Gum, Xanthan Gum, Carrageenan, Carboxymethyl Cellulose, Polysorbate 60 and Locust Bean Gum.
Sometimes the coconut content is described as 'coconut extract', I have no idea what that means.
Products marketed as 'Light' will typically have more water than coconut.
It is possible that in markets outside the UK there are 'better' canned products available.
I get Creamed Coconut in block form, which is 100% coconut and can be grated into the dish as required, where you can add such liquid as you choose and the gratings melt into it as it heats. You can also get this in sachets if a whole block seems like it would be more than you need.