From Graces Guide
of Belhaven Foundry, Morningside, Newmains, Lanarkshire
of Belhaven Works, Wishaw. (1908)
Belhaven built steam and petrol-engined vehicles.
Incorporated as Robert Morton and Sons and later re-registered as Belhaven Engineering and Motors
1907 Belhaven Engineering and Motors was registered on 4 May, for the purpose of carrying on the business of engineers and ironfounders, and of manufacturing motor vehicles of all kinds, and acquired the business of Robert Morton and Sons. 
The first of the Belhaven petrol-powered lorries used Tyler and then latterly Aster power units, coupled with the now proven chain drive transmission. These models were produced primarily as chassis cabs until their demise in 1924 when technology and the need to re-tool surpassed the capabilities of the Wishaw factory.
The majority of Belhaven owners had their vehicle bodies manufactured locally by John Stewart who set up business in the Coltness Coachworks on Kirk Road, Wishaw offering a custom built facility to coach and lorry operators.
1909 Produced a bus chassis suitable for a 30-seat body
1912 Purchased by Belhaven Limited.
1913-1917 For a list of the models and prices of Steam Motor Wagons, Tractors and Ploughs etc. see the 1917 Red Book
1914 Engineers, Iron and Brass Founders, Manufacturers of Commercial Motor Vehicles, Steam and Petrol. Specialities: Design and Manufacture of Bakery and Confectionery Plant, Coal Cutting Plant, Steam and Water Turbines, Creosoting Plant. Employees 200 to 250. 
The Belhaven steam bus ran between Glasgow and Eagleshaw.
The first two buses in The Fleet of Walter Alexandar were Belhavens.
Production ceased in 1924.
Sources of Information
- Ian Allan - British Buses Since 1900 - Aldridge and Morris
- The Stock Exchange Year Book 1908
- 1914 Whitakers Red Book