Some speculation, anyone? I know I could try it very simply, but it wouldn't be a simple matter if the database didn't remain intact. I can find nothing in Docs or the forum.

Ah. There it is. Searched 'database' rather than 'blog ID'.

You can't just change blog ID in evo_blogs table, it's linked across several tables and fields.

Thanks Sam. I appreciate the confirmation. Perhaps easier to start again afet saving content.