Malcolm, I have merged your posting and its replies into this separate thread as more people must be running into this problem.
I think
Hendrik van Oorspronk had the same problem, but I don't know how he solved it. I don't have the answer either, so let's hope that whoever finds a solution posts it here.
Indeed the SKF CR Seals website is an excellent resource to look up seals:
https://www.skfextranet.com/crsealsfinder/
(PS: SKF bought Chicago Rawhide many years ago but recently decided to reuse the CR brand as it still had an exellent name in the world of seals).