David, I had a further look myself today, and could not find much about Marlco other than it seems WDS bought the Marlco broaching part of the business and still uses the brand today, and I suspect the rest of it has gone.
I bought mine from a stall holder at one of the exhibitions when used tool dealers could afford a stand. It is really handy and I use it all the time. Mine came with a chuck fitted which I have never removed, with inside and outside jaws.
Chris Gunn