Probably worth contacting Andy Rowlands, the club's 120 series registrar (he posts on here sometimes), as he has at least one (if not more) really early Amazons.
My Scanner isn't set up at the moment but I can try and send you a photo of the green book page. There are 3 diagrams shown but I guess you need the last one for cars with Chassis numbers above 43000. I had a '61 and Ch# was over 60000. If your profile addy works it'll come via that.