Well, the 'Application Sharing' screen shows that nothing is assigned, to my PS3 or anything else. I could reapply the default set, but not my own.
However, it looks like I might have fixed it, by tricking the system. I applied my set to a different item (my Macbook Pro) and then changed it to my PS3, and it seems to have worked. I'll check everything is ok on my PS3 first before saying it is perfect.