Aluminium offcut (Fakenham NR21)

I am looking for a piece of aluminium plate that is 1/8" thick by 2" or so. Or a piece of channel section 1/8" thick by 3/4" x 3/4" by any length over 2". Size is not critical but thickness needs to be a minimum of 1/8". I want to make a heatsink with it for an electronics project.