I figured it is a Broxton regulator, but then realized it has no locating tabs on the box or drillings in the valve body to accommodate them. Every Broxton I've seen has them, but I'm no expert It has a two piece IP spring retainer/adjuster, not the one piece Spaco type, but that could have been upgraded.
![Image](https://i.imgur.com/Bdd6Z3L.jpg)
![Image](https://i.imgur.com/RNZHth6.jpg)
![Image](https://i.imgur.com/8N67wwC.jpg)
Any opinions? I'd be grateful for any help!