Flois. It is coming across that you are annoyed because there isn’t a store near you. And as a result, you are annoyed at their website.
But their website is very simply laid out. Their sizing is consistent. If you are a 10 on top in UK sizes and 12 on the bottom, then you are a size small in tops in Cos and a size medium in bottoms and dresses.
Their clothes have an interesting cut and tend to be more generous with the amount of material, and are cleverly cut to disguise rounder stomachs eg using side zips instead of front zips, pleats etc. The weight of their fabrics is usually heavier than other shops but I’m at a loss as to how you expect them to portray all that on their website any more than any other shop does? They give full dimensions, size of models etc.
I sometimes buy from Anthropologie and find the Cos website gives a huge amount of information in comparison.
As with many shops, Cos may suit some figures more than others. For people like me with a mum tum and non existent waistline, it is my go to place and more than half my wardrobe is from there. There is a large store nearby but I buy the majority of my clothes including Cos online because shopping with small children is not enjoyable.
I hope this post comes across as helpful as is its intention and isn’t coming across as me trying to be ‘cool’. Believe me I am most definitely not!