Will be trying to capture the problem next time, by using CamStudio.
;-)

Thanks, it would be helpful. We would also look into the drafts and see if there are any inconsistencies.

However, for larger edits I would recommend another workflow: create a separate category for drafts (does not need to be public), or even a separate site. This is how we do it when working on documents or blog posts. When changes are ready to be published, we copy content to the destination page. This way we keep the history of the published page clean, but also have a history of the draft, which we save from time to time. Sometimes we work on documents for a few days collaboratively, so the history of changes is really useful. We rely on built-in drafts for smaller edits.

If you are working on major changes to a page, please consider this workflow.

It is also notable that in auto numbered categories, no drafts are saved when you create a new page. Only after a page has been created and saved is when you can use drafts with it (in auto numbered categories).

If you're creating a page in an auto numbered category, be sure to save the page as soon as you create it, and then continue via creating drafts for it.

Having had 3-4 drafts VANISH on me (in the past 14 days), with a total of 2-3 hours of editing time,

Whilst the drafts feature is occasionally useful to me for small edits, in most cases when preparing drafts I rely on Shane's STE Wikidot Editor or the draft category approach.