1973 series 3 rhd 109 , I'm thinking about replacing the front seat for obvious reasons and I've either seen or read about people replacing theirs with seats from the junkyard. If you have done this please advise as to what seats are compatible and easily obtained at a junkyard. I'd like something to mount easily into existing base if possible, or a seat that can be mounted with a little modification. Thanks and any info is appreciated.