According to Arthur Ord-Hume, the Britannia appears to have been
produced post 1905.  B.H. Abrahams ceased business around 1909.

  "...the company seems to have been a latecomer to the disc
  musical-box market.  First to be introduced was the imperial, the
  earliest reference to which appears in the August 1905 trade
  catalog...."

  "The Britannia was virtually an identical instrument with
  the similarity (to the Imperial) extending to the case styles.
"A most popular model with collectors today is the so-called
  'smokers cabinet' 9" vertical which is called the Alexandra..."

Hope that helps!

Nancy Fratti - Nancy Fratti Music Boxes
Canastota, New York
http://www.nancyfrattimusicboxes.com/