I've just looked on Wiki and it was Frank Farian. The musicians he used were Robin McAuley and Bobby Kimball on vocals, David Paich on keyboards, Steve Lukather on guitar, Simon Phillips on drums and Curt Cress on drums. Far Corporation's cover of Stairway to Heaven reached number 8 in the UK singles chart and they also released an album, Division One (1985 IMP/ATCO) - which includes a cover of Free's Fire and Water. I think I've got the album somewhere.
I'm not a Zeppelin/Free purist, so this is okay by me. I love Bobby Kimball's voice. Robin McAuley does a good job, but all I know about him is his involvement with Grand Prix and Michael Schenker.