In the early 1960s, Compton introduced a model called the 'Augmentum'.  This was designed for churches with a tight budget.  The idea of the organ was that it was installed in two parts - firstly the great and pedal which consisted of 3 straight stops - Open Diapason 8', Octave 4' and Fifteenth 2' and a Hohl Flute at 8' extended down to 16' for the pedal.  A swell section was prepared for which could be added at a later date if required. The console was the same as those used on the 357 and 363 electrone models.

Very few of this model were built but one such installation that still survives is found at St John's Catholic Church in Stevenston near Ardrossan, Ayrshire.  In recent years the organ was overhauled by Michael Macdonald and the swell section added using pipework from other Compton organs and in keeping with what Compton would have done to give the following specification:

Bourdon 16'
Flute 8'
Tromba 16'
Great to Pedal
Swell to Pedal

Open Diapason 8'
Hohl Flute 8'
Octave 4'
Fifteenth 2'
Swell to Great

Hohl Flute 8'
Salicional 8'
Flute 4'
Salicet 4'
Echo Cymbale III
Tromba Bass 16'
Tromba Minor 8'
Tromba Octave 4'

4 double touch thumb pistons to Great and Pedal
4 double touch thumb pistons to Swell and Pedal
1 canceller thumb piston - Great to Pedal
1 canceller thumb piston - Swell to Pedal
1 general cancel thumb piston