Lost signature on Mail for Mac

[Jurek]

For some reason, Mail for Mac has stopped giving me the option of adding sigs to my emails.
When I click on the sigs drop-down menu it says 'none'.
But when I go to signatures in the mail settings, I can see my signature there - even though the 'select signature' box is greyed-out.
I've followed the online advice, to no avail.
This was working fine on Friday evening, but has since stopped.
Any ideas?

[ian]

It is added to the right account? What if you recreate it (copy it, then click the + and add a new signature)?

[Jurek]

Deleted the old one, created a new one - that seems to have sorted it.
Cheers!