Welcome, Ronnie. This is a rather slow moving forum but your questions have been addressed several times in the recent past. If you read back over the older posts, You may find what you are looking for. The "Search Community" feature is also a good resource.
There are quite a few British art supply sites. Jackson's Art is, based on advertising, probably one of the most popular British online art supply stores. They carry most major, and many not-so-well-known, brands of art supplies. Their offerings include paints, mediums, brushes, canvases and just about everything an artist might be interested in buying. You should be able to find the brands and quality of supplies you want in their catalog.
Google can be your friend when searching for art supplies, too.