Oak wall mounted telephone complete

Vintage 1951 Ericsson Wall Telephone with Siemens Brothers Handset, Wood Case, Magneto
 The diagram tells that it is a Ericsson Telephone Ltd Model 
The mark on the receiver is:  Siemens Brothers & Co. Ltd., London, Pat. SA 9/30 (1930).
Inside the case is an array of components as shown, plus a wiring diagram.
The inner wiring and magneto is complete.