In reply to humptydumpty:
V12 in Llanberis are the usual place for DMM stuff, and at the moment only seem to have the larger (04 blue, 05 silver, 06 purple) sizes on the site. Might be worth giving them a ring about availability of the smaller ones.
(The alpinetrek link above seems only to have size 4 available)
Post edited at 17:26