All I know for sure is that Lonesome Dave and a couple other Savoy Brown guys started Foghat, who I was a big fan of back in the later 70's. If Kim Simmons was associated with UFO that would be news to me but I'm not real familiar with UFO's history other than Michael Shenkar who became the guitarist with the Scorpions.
I will be honest and tell you and everybody else that I did not know that these guys became Foghat either without tracking it down.
But when listening to each, it makes sense. I think Foghat is simply a more rock than R&B sound. I think both are really good. Gun to my head I'd take Savoy.
I have a pal that's a total Savoy brown freak so I knew about the Foghat connection through him. Two great bands and I always thought of it like evolution.