I still have a couple of the old folded A5 sized blue lounge invitations from myold QFF Blue/Silver Status days. These are UNDATED. (I was a QP member back then so had little use.)
AFAIK, these were the only examples of undated invitations.
I received some further dated ones of the same type/format, but as these did have an expiry I ensured they were properly utilised.
