Image and header problem in Blocs 3

Just upgraded to Blocs 3. I have made a few adjustments to a site made in Blocs 2 - just a few text changes. Saved the site in Blocs 3 format after previewing it in Safari and Firefox. All looked great, so I uploaded it. The actual web page looks awful though. The images are now too big and overlap the text and the header has mysteriously migrated to the left hand side of the screen with a small rectangle (hamburger??) overlapping it. Site can be previewed here:

I have submitted a bug fault form on this issue, but any advice from the wider community would be much appreciated.

Thanks in anticipation