Kodak Wratten Gelatin filter no.12 ??????

Dear All,

I am a medical doctor looking to purchase a Kodak Wratten Gelatin
filter Number 12 for use in assessment of patients with dry eye using
fluorescein tear staining.

I have looked in a number of local photography shops, on ebay, the
kodak website and various other websites but have been unable to find
out where i can buy one.

Can any of you tell me where I can buy one in the UK (preferably via a
website or somewhere that will post it to me)??

Thanks for any help

Simon