[Stuart]

One thing I've noticed is the area where the path to the parade will be built is currently part of the Collins' garden- which must be around twice the size of the rest of the gardens on the close.

By the time the parade's built, the Dixons are living there, and I wouldn't be suprised if Ron was happy to give up some of his garden seeing as it was a path to his shop.

The width isn't the issue. This is the first wormhole identified in the universe, which can instantly transport you 7 miles from West Derby to Childwall.  Perhaps they wanted to avoid saying it was "bigger on the inside".