I doubt her merch sells particularly well, but she'll still be making quite a lot in ad revenue and every video she uploads is full of sponsor products and undeclared ads, so she'll be getting a lot of cash on the side.I don’t get how she can do what she does in London & be able to afford it especially as thing are now.
I don't know why she chose to live in London since she doesn't appear to go anywhere most of the time and her money will go a lot further elsewhere, but she can easily afford it for now.