I haven't done anything about the scrapes yet as I've been making improvements to the bike, but I'll report back when I give it a go. As for the primary chain, I included a Renold one in my most recent order from H; if you've got other stuff to fill the carton, it makes it worthwhile.
I met up with some of the guys from the club and out of the 5 of us, 3 were called Dave (yep, I'm a Dave too). We must be ubiquitous.