Hi, somehow I can't seem to reply directly to your 7546 post. This has happened a few times since the forum had it's improvements. Anyway I have three 7546 movements and none of them have battery retaining methods. None have any screw holes where it could be fitted and I think it's unlikely I have three all with the same fault. This I saw as one of the more obvious differences between it and the 7548. The case back seems to hold the battery, which is awkward as the large battery doesn't stay in place while you're working on the watch but I'm sure now they don't have one.