Well I certainly would never have considered a Vespa or Lambretta part!
I'm game though if you think the fittings would be compatible, and thanks for the heads up.
Looking at the Gutsibits site they seem to measure the length of the inner, so 895mm would be perfect, 900 would be great.
You can see how the radial caliper makes the cable take a much longer route.
I trial fitted an earlier cable guide I have, to give the curve of the cable more room. Having just detached the cable at the head and attached it to the gearbox to get a nice straight measurement of the extra length needed, I found that the curve is much sweeter and I think I can use the original guide.
Sad thing is, it looks like I will have to get new brake lines as well as the nearly new Hel lines appear to be too short!