Can anyone id this rotor ?

[UK 58 apache]

Hi,
I've got a 58 stepside, but the frontend has been changed , I've been told possibly to a c10, no idea of what year.
This is the rotor but I can't order replacement parts until I find out what it's off?
It's a 5x5 pcd with 1/2" studs if it helps.

If anyone can give me an idea , would be much appreciated .

Many thanks


I'm hoping my photos come out, new to posting photos,