My Boxer is 16 months old, he barks at every little noise inside and out and refuses to come in when out in the garden unless bribed with a treat.
Anyone have any ideas how to stop unecessary barking and retrieving him from the garden.

Id stick him on a flexi lead or long line for the garden that way he wont be able to ignore your commands for him to return to you. The barking's a hard one,I trained my dog the shhh command everytime he barks I say shh and he ceases barking.You could  try this by when he barks say shhh and when he stops give him a treat.Something like a bit of cheese or sausage.Good luck

Mark

Personally I prefer the water bottle techique-whenever he barks you say 'quiet' and squirt him in the face with water! :p Works with most dogs pretty quickly and the wonderful thing about it is, he is not getting any attention from you all the time he is making a noise. Then when he stops you can make a fuss of him. :-) I agree with Mark's suggestion about the flexi or long line. That way he doesn't have a chance to get it wrong and can still have the treat when he gets in, but as praise rather than bribery. ;-)

Boxers are a guarding breed. It is natural for them to alert you to noises, strangers, anything that they consider out of the ordinary. I usually go to see what mine are barking at and then say 'enough',  a command which they have been taught means stop whatever you are doing - from barking to getting OTT in play. If your dog refuses to come to you when first called then go and get him. If you keep calling he is learning that he does not have to obey. Train the recall using a long line as suggested.

I do the same as Shadowboxer with Glazby.  If he's barking in the garden I will get up, go and have a quick look and then tell him "Enough Now" which is the command he knows to stop barking.  We can then tell him to "Settle Down" and he'll find himself somewhere comfy to lay down.

Thanks for all your replies. We're going to give the water thing a go and the flexi, hopefully if we persist we'll see some results.