Yes, I figured that out and used Firefox which doesn't do the HTML thing on spaces.
Now the files come out with dates on. I found Fredos instructions (see attached image) and renamed the folders accordingly as the names were differently written on mine but that just gave me an error on opening SketchUp about it now being able to load the plugins, at which point I gave up and trashed them. There is some problem on Mac with unzipping these particular files and I don't know why. I unzip stuff all the time without the file names getting messed up like this.