could anyone tell me when the chewing and the giddy behaviour starts to go.also will the mounting anyone and everything calm down?

Phew! It's not just me, then :)

Zach is starting to calm down at 6 months, but he's still a giddy kipper when we go out.

try having him neuted ( I think he has to be 6 months for that)that will help and as hes a puppy they do like to play and be giddy .
Have you thought about puppy traing classes Lottie on here does dog traing and i am sure will be able to help.

Phew! It's not just me, then :)

Zach is starting to calm down at 6 months, but he's still a giddy kipper when we go out.

Badger is 2 and still has his moments.