I ordered my Wella paddle from the Netherlands, get this, Wella uk won't sell to anyone except Wella salons, but go across the pond and their tools are for sale cheap from wholesalers. I don't get these companies sometimes, did you know koleston perfect is box dye in America? Anyways I digress, just google Wella balayage paddle, I'm sure it came up on shopping results, €2.95, the delivery was more expensive so I bought 3 to have back up.
The sibel highlight board is widely available in the UK online but it's not very comfortable to use for long periods of time.