Fast forward to 2016. Seiko decided to bring back the Turtle. A few new turtles were born out of the mother 6309 (here’s a side-by-side comparison of the 6309 and the new SRP777). There are two variants, a Suwa and a non-Suwa dial. As with other vintage Seikos it indicates whether it was produced in the Seiko Suwa factory in Japan. The Suwa-dial was used between approximately 1976 and 1980. Although the core is still the same, there were some changes involved… More at Fratello.
If you want a mechanical watch for less than £400, there is no better option than one of the turtle variants.