@samho1234567 You can limit your download: 
A. https://josm.openstreetmap.de/wiki/Help/Action/DownloadObject (enable "download relation members" ) 
B.  https://josm.openstreetmap.de/wiki/Help/Action/DownloadAlongWay (by selecting single or multiple road segments) 
C. Download incomplete members  https://josm.openstreetmap.de/wiki/Help/Dialog/RelationEditor 