The little Norfolk Terrier is considered to be a good breed to have in the city since they are often able to adapt to the confines, the city noises, and the activities that are normally found in an urban environment. The drawback with the little Norfolk is that they are considered to be a good watchdog and they also tend to be one of the breeds that may bark a lot, so some training will most likely be necessary.
Having access to the garden will probably help to provide extra room to roam, but you may have some trouble with digging. Some people set aside a spot for their dog to dig in order to set up an appropriate area for activity. Take some time to look into digging management if this becomes a problem.
Another idea would be to have a family member or a neighbour drop in to spend some time with your little guy or perhaps even take him for a walk.
Hope this helps,
Zena & Zippy