I have now tried upping the memory limit in wp-config.php but the problem is still there.
It seems like I can change the bg-colour of something like the footer once but then cannot change it again for a day or two. Enfold>>Styling>>Footer
(eddited to add) I haven’t tried many other settings/changes so don’t know if the problem also happens in things like font or layout changes.
I have also re-checked that it is not a caching issue.
I still have not been able to get it to work on the above server but I loaded an example of it onto a 1and1 account and it works fine with both WP3.5 and WP3.6.
Is it perhaps a compatibility issue with PHP? I don’t know much about these things but is there maybe something I need to put into a .htaccess file?