Simon,
Here are some pics of my original dash-1 clutch pressure plate. It appears to be the stock Ford 11" long style that had the protruding counterweights cut off either by Ford or by De Tomaso. Note the isis stamp.
I don't have a confirmed part number for a McLeod dash-1 replacement, but I suspect that part number 360505 will work due to not having protruding counterweights. It's the pressure plate that is used with the dash-2. The dash-1 clutch disc needs to have a 1-1/8" x 10 spline hub.
John