Bath Large Vertical Duplex

A number of single vertical obliterators (10) were registered from 9^th November 1870 to the 27^th April 1881 (and perhaps beyond, destroyed by the fire in 1954). The cancels registered from 1870 had no dot after the “53” until in 1874 they gained a dot (“53.”).  In 1881 they reverted to no dot (“53”).  Here's an example of one with a dot (registered between 1874 and 1878) used to cancel a newspaper wrapper in 1880.

This brings up an aspect of the internal working of the Post Office that I don't understand.  This newspaper wrapper originated in Beckington which is only 3 miles from Frome (a Post Town) yet it would appear based on the cancellation of this wrapper that Bath was its Post Town even though Bath is 10½ miles to the north.