Mains water flow reduced - found this in pipe.

[Mikmikmikmik]

My mains water flow dropped off the other week. No leaks, pressure good. Elbow fitting from Toby copper pipe to plastic pipe just inside my garden. Turns out there was a piece of plastic in my pipe, couldn't go any further into my pipe so plumber was able to pull it out after opening fitting.
Anyone recognise this cos it must have come from the water boards pipe in the street and got stopped from going any further cos of size of my pipe, but was enough to cause blockage and reduce the flow a lot.

 

[Alpha man]

It looks like the remains off a plastic non return valve?

 

[Mikmikmikmik]

Could that be part of a plastic Toby that water service put in a few years back cos the old one seized?