Callaway Gardens has not been plotted in the correct location as the aerial footage on Bing Maps is from when it was a hospital 10 years ago.
The road from the entrance off Hospital Road goes up to roughly level with 12 Leighton Gardens, then bends round to roughly by the marker, then straightens out to roughly parallel with the Butts and heading for the garage between 82 and 97 Studland Park.
The ultimate layout of the estate is roughly as drawn, except it needs to be further to the east - the eastern part is much closer to Studland Park (the whole site includes the paler land in a line from the existing grey area to roughly level with the edge of 93 Studland Park).
The garden area in the middle is also not a 'communal park', its really not that big!
Sorry, but I do not have the skills or technology to edit this myself, but if you take a look at the OS map or the planning application map you can see what I mean.