The QQV07-40 is a dual beam tetrode for RF power amplification up to 250 MHz. The envelope says QV07-40 which was the original Type designation. Mullard changed the nomenclature in December 1948.
The construction style is of the American pattern of two separate electrode assemblies as is the case with the 829B and the smaller 832. The European pattern of double beam tetrode for RF power amplification can be seen in QQV03-20.
The twin electrode assemblies.
An anode seen end on.
The anode connections.
The wide glass tube envelope is 52 mm in diameter, and excluding the B7A base pins is 86 mm tall.
Reference: Datasheet. Type QQV07-40 was first introduced in 1948.