I'll give it a try.
This is the description in Egun, translated:

"John Rigby sidelock double rifle
Ser.Nr. 17459
Kal. .470 NE with 2nd barrels in .375 H&H
with RISING BITE
in a leather case
double triggers
length of pull 37cm, barrel length 470 71cm, barrel length 375er 65cm
The exchange barrel in .375H&H was made for the previous owner by Waffen Krausser, Munich, and was proofed in 1971.
With Suhl claw mounts and a Schmidt & Bender 4x36 Abs.4
Escutcheon in the stock without any engraving
Gun comes from German high nobility.
The original stock was raised by 3,5cm."

So, once upon a time before WWI somebody with money, taste and knowledge has the rifle made.
...
Big gap, records from Rigby and information by the seller might yield some detail...
...
In 1971 the owner (either degenerate nobility or some newly-rich) discovers that there is no .470 ammunition to be found, and has the .375 barrels made. The scope is not for night use (not in fashion then in Germany), its actually a sensible allround option. I expect the new barrels, mounts and scope to be technically sound and useful. And because with the scope the original stock had too much drop and because so much money was already spent (my estimate is around 4000 german marks back in 1971), a cheap way to corerct this was used.
At least they did not throw away the original .470 barrels ........

By the way asking price is Euro 29500.

fuhrmann