WHen the Gunner card comes into play, and you get to re roll your attack die. Does the defender get to re roll evades again or no?

You are not rerolling dice with gunner. If your attack misses then gunner lets you make a completely new attack and you have to work through all of the attack steps again. Choose target, roll attack dice, spend tokens and such to modify attack dice, and so on. Including the defenders defense roll.

Oh SoI can also choose a new target, very nice. Thank you.

You can choose a new target or try and hammer the target you originally missed. But as Forgottenlore said, it is treated as completely new and separate attack with the only restriction being primary weapon only.

Thank you Gents very much