My sympathies also....

@Gleni - getting in quite late. Glen so sad for you. I know that when we grow from seed we always have a special affinity.

I don't know about this leafhopper or what might work in your country or what can be used.

For future reference:

I had some leafhoppers that were devastating a Brugmansia. Fortunately I caught them early, but they had caused a lot of damage. I used a systemic. In addition, I had to repeatedly spray with Neem oil and rotated with Insecticidal Soap. ~ 10 applications each. I too had the black fungus caused by the honeydew. A common malady when a plant is attacked by mites, white flies, mealybugs, scales, etc. For that I use a mixture of 10 % bleach/90 % water. For smaller plants, you can spray it on, allow to sit for awhile and wipe with a sponge. With the smaller plant/sponge combo it cleans it up quickly.

Again - sorry for this loss.

Kind regards,
david

Thanks @DavidLMO. I have written down your comprehensive techniques and will use them.

I have just raised two more seedlings to try all over again. One just has to live long enough, though.

Cool!! Tenacity and perseverance are great traits. I wish you the best of luck.