Complex sentence: Antoria is the UK brand associated with guitars made in the Fuji-Gen factory in Japan in the 1970s; the same factory that produced Ibanez, and reputedly CSL and Columbus "copy" guitars.
Split into simpler sentences: Antoria is the UK brand associated with guitars made in the Fuji-Gen factory in Japan in the 1970s. The same factory that produced Ibanez, and reputedly CSL and Columbus "Copy" guitars.