I added a couple of roads in my area just using the online editor, seems fine but I can see a bit restricted. I have now downloaded Meraartor, seems fairly intuitive. It is certainly an advantage not having to upload the .gpx files. Especialy since there seems to be a problem at the moment, I just get a 404 error.
I am happy to help when I can, just need access to your .gpx data.

Sam, I am happy to help. I also live in Perth (Sawyers Valley). I know the south west very well. I am new to OSM but it looks not that difficult.