Service valve leaking, odd size

[Gary78]

Hi there,
The service valve on the water line, for the cistern, is leaking. Struggling to find a replacement as it seems to be an odd size, 15mm compression fitting and 3/4 inch screw on, on the other side. Anyone know where I can get one? Google searches coming up blank.

 

[WC1]

Is it a "female Stopcock" (no, really!)
And a "male iron" fitting on one end?

 

[ShaunCorbs]

https://www.NoLinkingToThis/p/straight-service-valve-15mm-x/58008

straight or angled

 

[WC1]

Sorry, I read Stopcock not service valve

 

[moonlight]

Do you have a picture?