Hi Rob -
You should be able to get them from:
DZUS Fasteners - Quick release fasteners, quarter turn fasteners ...... Tel: +44 (0) 1252 714422 • Fax: +44 (0) 1252 712738 • Dzus Fasteners, Farnham Trading Estate, Farnham, Surrey GU9 9PL, UK.
They have a minimum order I think and might point you in the direction of a retail outlet although Malcolm has sourced fasteners from them in the past and I think if you mention 'school/college project' it sometimes helps /ubbthreads/images/graemlins/grin.gif