paper

some papershops in london
Sheperds Falkiners - http://store.falkiners.com/store/
Atlantis - www.atlantisart.co.uk
Cass Art - www.cassart.co.uk
London Graphic Centre - www.londongraphics.co.uk
Paintworks - www.paintworks.biz
Canonbury Arts Ltd - www.canonburyarts.co.uk

some papermerchants (these supply paper to printers but you might be able to get samplepapers)
GF Smith - http://www.gfsmith.com/
Frederigoni - http://www.fedrigoni.co.uk/
Antalis - http://www.antalis.co.uk
Robert Horne - http://www.roberthorne.co.uk/
Munken / Arctic - http://www.arcticpaper.com
Arjo Wiggins - http://www.arjowiggins.com/index.php?lang=en