Plz help with coin ID [решено]

Hi all, I was given a coin collection when my grandfather passed away in 1990.

I believe it predates many ancient roman coins I have seen?

This coin is 35mm in diameter and approx 2.9mm thick. The markings are on the front and there is nothing on the back.

The coin feels metallic and heavy, maybe  bronze?

Any ideas guys?

Thanks in advance 

Chris

 My ideas: 

· Made in last few hundred years - due to perfectly round shape;  

as in ancient coins were irregular round shaped. 

· Someone then smoothed away both sides; 

the marking maybe then from engineering experiments. 

 Wait to hear what other members think as well. 

I would weigh and try some filters like that:

https://en.numista.com/catalogue/index.php?r=&ct=coin&im1=&im2=&tb=y&cat=y&ru=&ca=3&no=&v=&i=&b=&d=&u=&a=&dg=1800-1900&m=np&f=&t=35&w=&mt=&g=&se=&c=&wi=&sw=

Anyway my guess is that the coin is gone and now is just a piece of unknown metal with a lost history.

The only thing that remains on this coin is a part of a circle on the first photo from the 10 hours position to the 1 hour position.

Somehow it remembers me of a Cartwheel Penny, and given the size and thickness it may be possible.

 Could be. 

So the British Coin Museum feels it could be a worn 1797 George III penny that has had markings added afterwards. I seem to agree with the above answers. thankyou for all of your help