You can buy a replacement extrusion. But you need to confirm what size furler you have before you can order a replacement. You can find the specs for the FF1 (and FF2) here:
http://www.sailcdi.com/flexible-furlers.
The length and diameter of the forestay determines which size CDI you should have on your boat. (But don't assume a prior owner installed the right size. Check it yourself)
FF1
Main Stay Length: 21'
Maximum Wire Size: 1/8"
Luff Dimensions: 0.5" x 1.3"
Luff Tape: #6
Drum Diameter: 3.5"
Turnbuckle Size: 1/4"
FF2
Main Stay Length: 29'
Maximum Wire Size: 3/16"
Luff Dimensions: 0.6" x 1.4"
Luff Tape: #6
Drum Diameter: 4"
Turnbuckle Size: 1/4" - 5/16"
As you can see from the above, the FF1 takes a 1/8" diameter wire, and the plastic luff extrusion is 0.5 x 1.3"
The FF2 takes up to 3/16" diameter, and the plastic luff extrusion is bigger, 0.6 x 1.4".
Also, looking at that picture, it's unusual to find the black plastic slider on an FF1 or FF2. The black sliders came on the FF6 and larger models. So that's making me question what size the luff dimension is. I hope it's not a big sized FF6 which somebody cut down to use on your little Hunter.
The FF1 and FF2 extrusions are different sizes, so you'll need to confirm the size of the plastic luff which fits into the drum at the bottom. A picture of the drum with dimensions would be good too. It's a little difficult to tell how old the drum is from that picture.
The SBO chandlery can probably order the replacement part for you, or you can find it elsewhere on line.