1) He will do his business in the garden happily but when I take him for a walk he just will not pee or poo anywhere in the open grounds I take him to or the park! He will sniff around and whine to go but will not do it until we get home and then he will go in the garden and do his business. How do I get him to understand that walkies is about relieving himself?
Not sure what to make of that, but I assume it's something he will pick up eventually. You could always try bringing him to a park and letting him play there until he has no choice but to go to the bathroom, then rewarding him with praise and a treat when he does.
Just be careful about giving out treats when your dog goes to the bathroom. My GSD is very, very food motivated. When I started giving him treats for going to the bathroom outside, he started going to the bathroom inside too hoping he'd get a treat. I stopped that tactic immediately.
2) This issue is a little more concerning for me (I suppose). I have noticed that when we do go out for walks (please note we have been about 6-7 times in the last few weeks not everyday) he will:
i) Sniff alot and look around alot.
That's just him being curious.
ii) When he sees other dogs he shys away or sits next to me. I have not really made any effort to take him nearer to the other dogs. I think I am little vary that they make attack him. Yesterday evening I met a person with a 3 month old GSD (approx half the size of my dog) and yet my dog was shying away and hiding behind me whereas the other puppy was more confident and even growling/barking at my dog!
He just needs proper socialization. Do you know other people with dogs that are friendly? If so, arrange play dates. Don't be too concerned if your dog is wary of other dogs at first. A lot of puppies are. Just give it time and keep exposing him to other (friendly) dogs and he'll warm up eventually.
iii) On our walks I keep getting the feeling he just wants to go home as he pulls alot on the way back yet walks calmly when we first start out on our walk. That could be down to him wanting to go for pee/poo but I am not sure.
My GSD did the same thing when he was a puppy. I never really did figure this out, but I think it was just because he was intimidated by the world and wanted to go home. He'll likely grow out of it just like mine did.
He is very friendly with other people and sometimes gets too excited to meet people. As I mentioned above we have only been out a few times mainly because we have alot of ground around the house for him to roam around in and hence he is not couped up in the house. Though I must say he prefers to stay inside the house most of the day if he got it his way.
Just keep taking him out and letting him meet people. You probably want him to be really friendly with people, so encourage it by letting him meet as many as possible.