Well, i was thinking, if i got the actually largest population postcode in the area
eg.
BS10 - 40000 people
BS20 - 103000 people
BS92 - 19000 people
Id pick up the BS20 and develop it, as it will be most likely, to be the inner most postcode, so be the code for the center of town, or would that not be the best idea, and would it be better to have a site for more residential areas?