Found by Ian Suddaby in the High Bonnybridge area.
This example is not in my possession.
Bonnybridge Silica & Fireclay Co Ltd, Bonnybridge.
alt
Calder Firebrick Works, Airdrie, Lanarkshire.
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Chapelhall Works, Lanarkshire.
Hepworth Ceramic Holdings plc (GR-Stein Refractories Ltd. parent co) bought the Bonnybridge Silica & Fireclay Co. Ltd in 1972, closed Bonnybridge works in 1973 and closed Chapelhall in 1980. Therefore between 1972 and 1980, GR-Stein Refractories probably continued to manufacture bricks with this trademark for a time.
Following on from the research related to this link which supplies highly probably evidence that Scottish brick manufacturing companies were manufacturing bricks for the South American railways, then I believe that GIPR stands for the Great Indian Peninsula Railway.
Like most of the early railways in India, the Great Indian Peninsula Railway (GIPR) was a British company, registered in London, privately owned and financed, operating under licence and guarantee from the (British) Board of Control in India and the East India Company (EIC). The GIPR was India’s and Asia’s first railway. Source