I've just found entries for the company in the PO Directories for Glasgow dated between 1926-28:
West George street. 37 . Wright & Pouncy The Denholm Manufacturing Co., Ltd who are listed as clock manufacturers and importers
and an undated entry also in the PO Directory for Glasgow:
The Post-Office Annual Glasgow Directory
The Denholm Manufacturing Co., Ltd., clock manufacturers and importers, Morrison court, 108
Argyle St., C.2