Hi Gareth,
Site is available on the web (I guess you mean accessible through browser)
Change theme via UTL is turned on, no effect
Theme designer is on, but I'm afraid I do not quite understand what you mean by the URL for the 'all' CSS file in the network tab of the browser development tools (F12). See a lot of tabs with F12, both in Chrome and in Firefix, but not sure which you mean...
In php.log:
[Tue Feb 27 09:38:33.530641 2018] [lsapi:notice] [pid 27599:tid 139723490072320] [client 80.57.196.118:61135] [host upgradelearning.cobytes.io] Backend log: Default exception handler: Coding error detected, it must be fixed by a programmer: Unexpected output whilst processing AJAX request. This could be caused by trailing whitespace. Output received: '\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n' Debug: \nError code: codingerror\n* line 77 of /lib/ajax/ajaxlib.php: coding_exception thrown\n* line 52 of /lib/ajax/getsiteadminbranch.php: call to ajax_check_captured_output()\n, referer: http://upgradelearning.cobytes.io/nimo/my/
[Tue Feb 27 09:39:13.976574 2018] [lsapi:notice] [pid 27599:tid 139723330610944] [client 80.57.196.118:61154] [host upgradelearning.cobytes.io] Backend log: Default exception handler: Coding error detected, it must be fixed by a programmer: Unexpected output whilst processing AJAX request. This could be caused by trailing whitespace. Output received: '\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n' Debug: \nError code: codingerror\n* line 77 of /lib/ajax/ajaxlib.php: coding_exception thrown\n* line 52 of /lib/ajax/getsiteadminbranch.php: call to ajax_check_captured_output()\n, referer: http://upgradelearning.cobytes.io/nimo/course/view.php?id=72