This old amplifying stage was found in radios and small amplifiers of the time. The circuit is from Mullard's transistor reference manual.
Texas Instruments ESD122 Electrostatic Discharge Diodes (ESD) can be ordered from Mouser...
This alternating flashing system uses two-color LEDs. The circuit is from a Radio Electronics...
I found this simple circuit from an English magazine from 1984. The circuit can be easily...