Hi Pip,
I have wide array of them. 6138, 6139, 6309 Classic turtle as well as slim case. I also have 7a28, 7a38, 7a48, 7002, 7549, and recently 7548. Latter is what I am trying to figure out. Second hand twitches with a new battery, so I am thinking there is life left. I also have mordern Seiko Divers. 62Mas reissue (SBDC051), and SRP lines as well as, SKX- 007, 011, and 171.
How about you?