The LM3914 is a monolithic integrated circuit that functions including “staging” control can be senses analog voltage levels and drives 10 LEDs, performed. The LM3914 can also act as a providing a linear analog display. A single pin programmer, or sequencer. changes the display from a moving dot to a bar graph. Current drive to the LEDs is regulated and The LM3914 is rated for operation from 0°C to +70°C. programmable, eliminating the need for resistors. 

the IC has a 1991 date code

The LF398 devices are monolithic sample-and-hold circuits that use BI-FET technology to obtain ultrahigh DC accuracy with fast acquisition of signal and low droop rate. 

Is this a 1984 date code ? On the same board as ICs with 1991 codes

The 741 is a bit of a classic op amp, nice to see it in this bit of GPO test kit.

There have been 100s of millions sold since its invention in 1968 according to The internet 

But its not as old as the TXE2 design !

Original leaflet beautifully preserved by Sam at http://www.samhallas.co.uk/repository/handbooks/tester_286a.pdf 

INTRODUCTION 

The SCOPPLE* electronic test probe is a product of Southways Electronics Ltd., manufactured under licence from Standard Telephones and Cables (STC). The unit was originally designed for STC installation staff to use when installing TXE4 telephone exchanges for British Telecom -part of the Post Office. It has now been adopted by British Telecom as PO Tester No 286A. 

The SCOPPLE operates from the exchange power supply jacks on telecommunications equipment racks. These supplies can range from -44V de to -66V de and the SCOPPLE is designed to operate over this range. A plug-ended lead is provided for insertion into the power jacks.