http://www.mutr.co.uk/ is their sales site - and highly recommended if you want to play with weird materials and other science stuff - I think they'll take orders from the public as well as schools etc. but I haven't checked.
The microcentrifuge is here
It's stripped down to the bare essentials with an emphasis on safety, and you can even run it on batteries if you want to use it in the field. Hopefully placing an order tomorrow.