Does not appear any standard way of indenting text. However see method described in Test Pages
To add space between paragraph blocks I had to add a paragraph with a single blank character.
Sometimes, especially with photos in multi-column elements, things appear to go missing. Most times these can be recovered by just temporarily clicking on another page in the menu and then clicking ob the original page again. On return all is usually fine and missing section back and all new work also present.
HTML page stopped displaying in edit when it reached <div style="float:left;"> but the page did display properly when published. Simple <div> statements seem OK, so I suspect the float is the problem, especially as Custom HTML element has the ability to set float.
See above. Just discovered if I put text or   which is a no break space command between </div> and next <div> then all appears in the editing window.