Thanks all, I worked this week (I’m semi retired, work when someone needs help) so haven’t tried anything yet.
Yeah, there’s a box, and yeah, it’s buried. Don’t know the age of the valve but dirt has made it’s way into the box and packed tight around the box. I have attempted my best archeologist impersonation and exposed the top, and old Watermaster - I think an Orbit solenoid should work so I’ll try that first.