Paxman of London Eb sousaphone 3P (maybe only the bell is by Paxman - the story is in the caption of the photo of the bell engraving)
5. Bell engraving
Paxman started out around 1920 by converting surplus WWI army helicons into sousaphones for the many dance bands of the pre-amplification era. So maybe only the bell is by Paxman
6. Front view