[Amps] identification of a rectifier

[CLIVE COLLINS]

Can anyone help me with details of a rectifier please.
  I suspect it is the solid state replacement for a 8020 EHT half wave but I cannot find a makers name anywhere or positively identify what it is.
   
  The print on it shows   "CG 5961-01-GL2-3409" followed by "ED5741  EDI 7550".
   
  The first set looks suspiciously like a NATO stock number apart from the "CG" and "GL2" bits.
   
  Any help would be very much appreciated.
  Thanks and all good wishes,
   
  Clive GW3WEQ