Force sync freezes and stops. Many missing images

Started in the last week or so, we seem to have lost many of our older images in the cache – affecting related posts and galleries. Turn off photon cache (image acceleration) and site is OK, but of course photon required to make both of the above features work.

Tried to do a resync all through “Data synchronisation” option in wordpress.com for several days and it just freezes each time and never gets anywhere even if left 12hrs or more (progress bar frozen), so doesn’t fix problem. “Diagnose a connection problem” tests says all OK.

Anyone have ideas?

The page I need help with: [log in to see the link]