Further Information (and imagine my surprise):
We shined a light into the vent hole and found the following label (pics attached):
Henry Potter was born in 1810 (the same year as John Clinton) into a family with a solid musical background. Henry’s father Samuel Potter (1772 - 1838) had enlisted in the Coldstream Guards at the age of 14 in 1786, and eventually by 1815 had risen to the rank of Regimental Drum Major. Samuel completed 30 years service with the Guards and resigned from the army in 1817 to set up a workshop located in King Street, Westminster for the purpose of making drums and wind instruments. Samuel seems to have concentrated on instruments with a military band connotation, such as drums, bugles, fifes, horns and trumpets. He actually wrote several published treatises, one being a method for playing the fife (1815) and the other being a manual for drums, fifes and bugles (1817).
Samuel’s son Henry (1810 – 1876) presumably learned about instrument making from his father, and continued the business after his father’s death in 1838. By 1841 he was well established as his father’s successor, with premises at 2 Bridge Street, Westminster. He continued in his father’s footsteps as regards the making of military instruments, but appears to have had a strong interest in flute making as well. Clearly he must have quickly built up a good reputation as a flute maker, since otherwise it is inconceivable that John Clinton would have entrusted the manufacture of the early Clinton-system flutes to him, in particular the 1851 Exhibition model. Henry Potter remained in the instrument business all his life, and his company remained active until around 1950. Source: John aka longjohn, Vintage Drum Guru.