Then there's this gizmo:
https://kickmagicstarter.com/
I saw this in operation recently. It seemed to work. There was no mention of mounting it on a Vincent. Not that I would want one on mine.
I will add that despite being rather short and riding a rather tall D Rapide, I don't seem to have much of a problem. When the bike is cold, I do start it on the D stand but never when even somewhat warm. My bike has a C-style front stand but I don't start it on that. I just take the bike off whichever stand it is on, swing my leg over and start with my left foot on the ground. I don't find the need to come off the seat. It does seem to help to make sure the engine is rotated to the compression stroke on the front cylinder. Then, it's a matter of putting some pressure on the lifter and easing the kickstart until the lifter lever moves in readily. Once in, I just give it a good thrust, letting the lever go at about the same time. One such kick is usually enough, unless someone I really want to impress is watching.