The CV5745 is the UK Government code for the commercial GZ33 rectifier and both Type designations are on the envelope.
The GZ33 shares base pin layout with the GZ32 and the GZ34. All are full wave rectifiers with a rating of 500 Volts for the anodes. The GZ34 is an upgrade to the GZ32 and both are rated at 125 mA rectifier current. The GZ33, however, is a high current version and is rated at 250 mA rectified current, and unlike its lower rated counterparts is not given a maximum reservoir current rating, but 200 µF would seem a maximum value that would be used in practice. The cathode is tied to one side of the heater as heater-cathode insulation would not be sufficient to withstand the full voltage.
The Mullard logo and GZ33 name as well as the Made in Great Britain wording.
The face view of one anode. The central cathode has a flat anode around it. The anode is wide to offer a greater radiating area to reduce heat build-up.
The classic envelope is 44 mm in diameter and, excluding the IO base pins, is 126 mm tall.