Hi,
it seems to me you are too easily assuming that having old AV definitions in a SEP agent is most likely due to an expired license. This assumption is not supported by the screenshots you attached here.
In SEP enterprise edition (EE), an expired paid license does not stop the product to get definitions.
This would happen in the small business edition (SBE), yet after a grace period. More about it in this article:
https://www-secure.symantec.com/connect/forums/cannot-get-sep-clients-communicate-new-sepm-server
Which edition do you have?
A client can be out-of-date for several other reasons such as communication issues, broken definitions, no disk space, etc.
Now, I am also not 100% sure of how to check if that date is in US or UK format but, as you pointed out, if that license is expired (and you have a SBE) you should have 20 clients out-of-date. As result, my current understanding of the whole situation is that the 20 seats license is close to expire (or expired?) but that system is not getting the latest definitions for different reasons than licensing. In that SEP agent you should also get some warning specifically about the license status, if that's the issue. You may also review that SEP agent system logs to spot errors and warnings about licensing and content update.