Now we have it as a spreadsheet we can do lots of different things, but I am against having separate lists as that means you have to update both of them every time something changes.
When opening the new list just now it is read only, but people can use the tools in Excel to sort the list any way they want.
I quite like Annie's idea of putting an asterisk (or and asterix!) next to the models where there is more than one conversion or even putting a number in brackets to show how many there are, as there are lots of Kingfishers out there. At least with her idea the additional ones are on the same workbook, and we would only need to add some text to tell people what the asterisk or number in brackets means, and how to find the extra boats.
I felt it was worth showing on the main list where there are different rig types on the same hull, as this makes it easier if people are interested in schooners, say, or swingwings.