Restore will only work to the same version of C5 as the backup was made from. Anything else, and either the restore will fail, or the resulting site will in some way be corrupted.

So:
- Load the files for the version of C5 the backup was initially made from
- Make sure all the relevant /files subfolders for your site are in place
- Delete the content of the cache folder
- Then restore from the backup. The error could be that your site ran out of cpu resources during the restore, so it may be better to restore by importing the sql using phpMyAdmin.

Many thanks for this - working on it now - will advise

Thanks

David

Sorry but can anybody advise me as to how to uninstall the latest upgrade so I can restore to an earlier point.

The text that I stated as lost is in fact there in edit mode within the blocks but does not appear on the page.

Thanks

David

If the previous c5 code is present, you can change or delete the constant DIRNAME_APP_UPDATED in config/site.php.

Don't do this unless you also have a database backup for the site from the c5 version you are dropping back to. You will probably need to use phpMyAdmin to restore/import the backup because between editing config/site and making the restore, the c5 core you are using will probably be incompatible with the database.