I have not been able to find out that much about this model or the company - the airbrush has these markings;
COLOUR SPRAYS LTD LONDON and the model number 5018. If any reader can supply more information, I would be grateful.
I have once again included a link to my Dampf's Wargame Terrain Survey and would welcome any answers to the three simple questions. For more information on the survey, see this link for details.