In 1943 Mr. J Gilbert Mills was appointed Organist and Choirmaster. A well-known recitalist in his day, and a one-time Birmingham deputy City Organist and a frequent broadcaster from the Church of the Messiah in Birmingham, Mr. Mills set about the improvement of the organ as soon as possible after the end of the war in 1945. Under his guidance the instrument was comprehensively reconstructed by Robert Spurden Rutt & Co. of London in 1947. The Swell chest was turned round to bring the Trumpet rank to the front of the box, the Trumpet was fitted with harmonic trebles and a Vox Angelica was added. The case front was widened and moved eastward together with the console. The original 4-slide Great windchest was retained and used for the 8ft. Open Diapason, a new 4ft. Principal, a second-hand 8ft. Gemshorn (to tenor C only because of lack of space for the bottom octave) and an 8ft. Stopped Diapason which replaced the earlier stop of the same name. A new unit chest was provided to accommodate the 4ft. Flute removed from the old slider chest together with two octaves of new Bourdon pipes to give Bourdon 16, Flute 8 and Flute 4 on Great and Pedal. Further unit chests were provided for the old 16ft. Violon and 8ft. Geigen with two new octaves of pipes to make up a 97-note unit giving Violon 16, Geigen 8, Octave Geigen 4 and Fifteenth 2 on the Great; and Violon 16, Cello 8, Prestant 4 on the Pedal. The Pedal Bourdon was extended by an octave of pipes from an old cinema organ to give Sub-bass 16 and Major Flute 8. The action was converted to electro-pneumatic with a stop-key console and second-hand Rockingham blower installed. Some time later the necessary action switchers were provided to give Pedal Quint 10⅔ from the Bourdon unit.
The organ remained in this state (12 x Great, 10 x Swell, 9 x Pedal) until 1957.
In 1957 the 5-stop Chancel organ was added, played from the console attached to the main organ in the West gallery by addition of a third manual obtained from a redundant Compton cinema organ. It is enclosed in a swell box and has its own blower. The Chancel organ had originally been constructed by Rutt as part of the replacement organ for a London Methodist church which had been destroyed in the war. A change in the building plan resulted in the organ being too big for the space available; on learning this and seeing the organ part-completed in Rutt’s works Mr. Mills bought it, together with five ranks of used pipework which he chose from Rutts’ stock, and it was duly installed in St. Michael’s church. The simple pipe-front of the Chancel organ was given to Mr. Mills by the organ building firm Nicholsons of Worcester and he presented it to the church.