Minehead Undated Circular handstamp from 1920 ?

The Registered envelope below has a 20mm single ring "MINEHEAD" undated circular (UDC) handstamp on the Registration etiquette label, along with steel "MINEHEAD / SOMERSET" single ring cancels dated 15th October 1920.

In Somerset the single ring UDC handstamps were issued between 1857 and 1859, and did not include one to Minehead (the UDC handstamps were for village post offices).  Should this handstamp be added to the list ?

On consulting with more knowledgeable members of the S&DPHG the answer is No.  The undated 20mm circular handstamp is likely to be an ordinary circular datestamp with the date slugs temporarily removed, being used to identify the Registration Label at a time when the Minehead office did not have a named Registration Label.