Please advise me what was a purpose of this dish , is marked with Mappin & Webb’s Prince’s Plate Thank you 
You don’t mention any measurements, however it appears to be an olive dish with accompanying pit bowl for holding your discarded olive stones.
Appears to be a vintage silver-plated, two-section hors d"ouevres dish. The larger compartment is designed to accommodate a plain glass dish . There’s a number of similar three-compartment dishes registered on Ebay. Three sections seem to go for $32.
I think I rather like Red6’s idea for use but I suppose if you are spitting olive pits into the same or adjacent dish you’re taking them from, each guest would have his or her own two compartment container?
Reminds me of the Seinfeld episode where one funeral guest got cross with another for double dipping.
Hi there thank you for you ideas 
For the time being, your suggestion regarding the potential use of this vessel is logical. item is about 18 cm , the round part Ø is about 11 cm regards Peter
Thank you all for ideas Regards Peter