Local Bath slogan cancellations ....

The first use of a "one-town" slogan cancellation was in 1956 in Rochdale.  The first such cancellations were in "untransposed" format, that is the town cancel was on the left, normally clear of the stamp while the slogan cancel was on the right, normally over the stamp.
This meant that the slogan cancel was often not very readable.  As the Post Office was charging the local councils for the slogan publicity cancels the councils were not happy with this.

On 1st July 1963 Bath became the first town to use a local publicity slogan in the "transposed" position, that is with the town cancel on the right over the stamp and the slogan cancel on the left where it was more readable.