unordered list within a list editing problem

Hi guys (esmi!)

I seem to have created a problem with the layout on a page of mine. It has small unorderd lists within a bigger list….

https://handycrowd.com/how-to/plasterwork/repair-lath-and-plaster-ceilings/

Now the page displays fine, but it gets a bit of traffic so I like to update it from time to time, but when I open it in wordpress (in either view) the list has lots of extra code inserted <ol/>’s usually.

I understand not to switch between editors but this seems to be a problem from the start.

anyone know what I’ve done wrong in my code and how I can make it stable?
Many thanks!
Ian