Having been given access to a site plan of my daughters new housing estate, using it to trace from seemed a good idea. While it was provided as a PDF, it needed to be converted to an image to use with PicLayer and I took the opportunity to rotate the image so north was straight up. It was fairly easy to shuffle the loaded image so that it's right hand boundary almost perfectly overlayed the existing boundary in OSM and then information can be manually traced over. Progress so far and over christmas will add all of the detail for the area

Crib sheets used to get up to speed with and refresh how to use JOSM ... been a while siince I use it last.
Help on PicLayer
Demo of PicLayer