[ Ref. Julian Dyer in 241215 MMDigest ]

To add some more information to that posted by Julian Dyer and
others, the British Steck was made in both upright and grand styles.
To complicate the serial number discussion further, four distinct
series of numbers were used.

I have been keeping records of all Aeolian Co. Ltd., London,
instruments, including other makes fitted with their actions, such
as Steinway, for over 40 years.

There was a certain amount of "cross-fertilisation" involved, as
some British Stecks were also branded as Aeolians, but essentially
the numbering patterns were as follows:

1xxxx (5-digits): smaller upright such as the Model 1; more commonly
branded as Aeolian, otherwise identical.

2xxxx: baby grand Model 3H; usually electric-only Duo-Art.

7xxxx: smaller upright Model 7; usually pedal Duo-Art.

1xxxxx (6-digits): upright, usually Model 9; grand 5'6" Model 2H.

As Julian says, the Gotha factory used a 5-digit series which
commenced with 2xxxx.

[ 5xxxx: ] In the 1920s, the Aeolian Co. Ltd., London, appears to have
turned its attention to the stock and parts that it acquired from the
Gotha factory after it was sold, and I have seen several uprights and
grands which are hybrids combining both Gotha and London elements and
bearing a 5-digit number usually starting with a 5.

If anyone has a British Steck (or Aeolian), and would like to know
more, I am always happy to help.

Best wishes for the Festive Season,

Mike Boyd
Rye, East Sussex, UK
https://pianolarestoration.co.uk/ 
mike@aeolianpianola.co.uk.geentroep [delete ".geentroep" to reply]