Is it not time for a swap of males from Zoo Berlin (2.0) to Chester and vice versa (1.1)? How old are the Chester Zoo tuatara and which zoo did they come from?
given that the tuataras activity temp is around 12-15°C I highly doubt that they would be housed outdoors especially somewhere hot like SD
San Diego tuataras According to their website , they have Brothers Islands tuataras "offsite" This was part of their Reptile house page on their website