I got most of the bits from Farnell (IC's, diodes, LED's, Caps and resistors), and Maplin (box, 1/4" Jacks, LED holders, Knobs, and battery snaps) . The only things you cant get there are the TPDT switch and the PSU socket, these you can get from Ebay (Faith Healer).
I couldn't get a 5k linear pot so I got a 10K and strapped a 10k resistor across pins 1 and 3. I've checked it with a meter and its spot on 0 - 5Kohms.