The "Who" of Arab were J.G. Parry Thomas and Reid Railton. The Arab was made in Letchworth in 1926-7 but production had barely started when Parry Thomas was killed in a Speed Record attempt on Pendine Sands (3/3/27). A total of 12 cars were made including some put together from parts by Thomson and Taylor at Brooklands (where Railton had become Technical Director) after the company’s demise.
Here's a photo of one: