I decided that when (if) I ever repaint Khamsin, that the cost of new vinyl would be minimal in comparison.
Also, with a hot air gun/hairdryer the lettering would come off much easier than trying to neatly paint around it.
I used a company in Fort William and they were very helpful and efficient.
I have been painting around the letters on the transom with Toplac every 3-5 years or so. Mostly due to laziness in not wanting to take the name off and reapply. It still looks OK from the sort of distance it's normally viewed from.