There was a German piano maker named Schreiber, and Barratt & Robinson used the name, as did the Challen factory, so the name is not helpful on its own.
Would you please give us the complete, exact wording on the piano.
It would help if you could post photos here to show us what the piano looks like, or email them to me.
Have a look at
The serial number doesn't help, we have no number dates for Schreiber, and Murdoch pianos don't follow the same numbers. However, this is the nearest I can recall seeing to the numbers published for "Spencer-Murdoch", which would suggest 1905. That would suggest that this piano was made for Murdoch, and the name Schreiber is meaningless.
The majority of Murdoch pianos then were vertical-strung, this one is overstrung, so perhaps it is by Schreiber, Berlin? The action may be marked on the rear with the action makers' name and number, and I may be able to date this.
There may be dates inside, see
Any fool can make a piano-- it needs a tuner to put the music in it
I would be interested to know of you find any markings on the action.
Incidentally, I don't think Murdoch was at 461 & 463 much before 1918, so perhaps they sold it secondhand.