clamping of throttle cable

Too Late ! - I would never cut my surplus cable so short.

There is a clever technique, that I have seen on video (not tried) where you apply  a flame  to the surplus end, get it red hot at the point of separation,  and apply twist. The strands weld themselves together and eventually the twist action separates the cable, leaving a neat tapered finish.

I have also heard that a similar finish can be achieved by soldering - not so convinced of this.

You need the surplus end to stay neat/compact, so that any future removal/refix is easily threaded through the clamp hole.😈

I thought it was cut short at first, but if you look closely I think it's just sleeved with some black heatshrink making it look the same as the background.

I've tried the heat and twist technique but I think that you need some serious heat to get the strands to weld. I did have some limited success using solder with added flux. Once the strands are bound together then you can always file off any excess solder from the outside so that if still fits through the clamp.

I notice that bike cables come what appears to be a weld to the very end to stop it unravelling. There is probably a special machine used to do this.

" I thought it was cut short at first, but if you look closely I think it's just sleeved with some black heatshrink making it look the same as the background."

True! My apologies.

"I've tried the heat and twist technique but I think that you need some serious heat to get the strands to weld"

A propane (plumbers with small jet) torch should be sufficient, if Oxyacetylene not available.😈

Here are a couple of things I have done. 

https://waltsrv12.com/engine/the-perfect-ending-to-a-cable/

https://waltsrv12.com/engine/cable-stops/

I actually tried the solder approach (with plumber's flux) without success