It would be correct to say that the American type 80 led standard practice since in its earlier, more bulbous form, it was the landmark full-wave rectifier and (we think) the first mass-produced rectifier to use oxide-coated tape filaments. This exhibit is a later British implementation of the design.
The twin valve sections. Note the oxide coated ribbon filaments.
The anodes plates form a wide channel through which the inverted V ribbon filaments pass.
The maximum reservoir capacitor is 32 µF and the minimum series resistance, to limit current, is 30 Ohms.
The wide glass tube envelope is 28 mm in diameter and, excluding the UX4 base pins, is 79 mm tall.
References: Datasheet, private communication, 1040 & 1043. Type 80 was first introduced in 1936.