This is exactly what it says: an Autopiano action (from New York)
fitted to a London-made Eavestaff piano.  The fitting would have
been done by or for Kastner & Co, who had the exclusive dealership
for Autopiano in London (they have been mentioned in MMD on various
occasions).  They used a fairly wide variety of pianos, Eavestaff being
one of the cheaper ones.  Kastner later changed their name to Autopiano,
and production continued surprisingly late into the 1930s.

The UK-made Marque Ampico I have appears to be an Eavestaff, and is a
perfectly decent nicely-made piano.  I think that after 1925 they were
part of the Brasted group, Percy Brasted being responsible for developing
a Swedish design into the Minipiano (a tiny Art Deco console model) and,
even more improbably, making such a success of it that the design was
sold on to Hardmann Peck in the USA!

Julian Dyer