I do remember Radio Seagull in summer 1973 and to be honest, when it first started with Barry and Hugh, it sounded a bit alien to my young ears. I assume Geronimo would have been similar.
I was more into RNI at that stage, but have to say later in the year and probably when you were on the Mi Amigo Ian, the format seems a little more mainstream. I think that may have been the influence of Tony Allan. Still albums, but not the heavy stuff that my young ears were unaccustomed to.