The Bolsover Brothers produced an automobile steam boiler as early as April 1908, when it was featured in The Automotor Journal.[1]

During World War II, they offered a boiler for retrofitting petrol cars to steam, and published a catalogue entitled Bolsover Steam Car Components showing this boiler and a light steam engine.

The Bolsover Brothers Catalogue, 1924

The Bolsover Brothers Catalogue, 1942.

Bolsover Rogers Steam Engine, Octobe 23, 1942, Front Bolsover Rogers Steam Engine, Octobe 23, 1942, Reverse

This drawing of the Bolsover-Rogers Steam Engine is dated October 23, 1942.

[1]"The Bolsover Quick Steaming Boiler," The Automotor Journal: A Record and Review of Applied Automatic Locomobion, (Vol. XIII, No. 19, Number 383, May 9, 1908), P. 615.