Yep Somerset is an EUA town. NGrid was very random with spot replacements of the FCO EUA fixtures. Most of the time a drop lens light is installed to replace failed FCOs, but sometimes they actually install a new FCO fixture.
I'm glad you brought that up because for 250w FCO fixtures they would use OVHs as seen here, and for 250w drop lens fixtures, they would use M250R2s. Odd how they don't stick with one fixture.