In 1904 the Thresh Disinfector Company of 66 Victoria Street, Westminster, London, took out a patent for an improved Disinfector - a device by which low pressure steam was used to disinfect bedding and clothing. Hot air was also created within the appliance, enabling drying of the contents to also take place. These disinfectors, sometimes mounted on wheels (as in the case of the Beamish example), were supplied to the War Office as well as Crown Agents for sale and use across the colonies. They found use with Rural District Councils too – for instance in hospitals – and again these could be static or portable in nature. The London address was presumably an office, as it appears that the actual appliances were made in Keighley, West Yorkshire. They were fitted by the Yorkshire based company Summerscales.( I have also seem this quoted as Summersides). They were based at Phoenix Works Keighley.
Steam was introduced into the drum from the engine.
The doors on the drums hinge outwards.
Apparently the contents got quite hot and the Americans complained that the buttons on their uniforms melted.
Fitted with 2 large steel drums, clothing contaminated with lice and other vermin placed inside and then low pressure steam introduced from the engine, this killed all the little unwanted creatures and eggs.
In 1918 there were 90 of these Thresh disinfectors on the Western Front, 5 in Italy and 3 in Britain.
Built mostly from plastic card, with reference to photos and use of the book - The Overtype Steam Road waggon by Maurice A Kelly.
Once again accuracy may be a bit dubious but it captures the feel of the vehicle, I think.