Ok so that works fine, bit more fiddley than I would have liked but the end result is good. Firstly I had to bore the center of the cup to suit the shoulder on the Victa nut, then I cut 4mm off the top of the cup to get the height clearance and then I closed up the little wings on the inside for a bit more clearance in the diameter. It now catches every time within 4 inches of the cord being pulled
