Vandyke Engineering of Harlow in Essex were the manufacturers of the Type F box, introduced in 1968. These rectangular boxes were constructed of sheet steel. At the time sheet steel was seen as a “modern” material, as opposed to “old fashioned” cast iron. Both single and twin boxes with a shared roof were produced. They proved unequal to the task on the streets, succumbing to rust damage caused by weather and the attention of dogs.