Joomdev are still trying to sort out this issue.
In the meantime, the site has crashed again. It was fine yesterday and I haven't changed anything. Could you take a look at the response from my server and let me know if there is a way to fix it:
'There looks to be a missing class within the code this is not being caused by the server.
cjrrenovations-co-uk.stackstaging.com [Thu Aug 22 18:03:05 2019] [error] [client 220.127.116.11:0] PHP Fatal error: Class 'SellaciousPlugin' not found in /home/sites/7a/6/6a28a854cc/public_html/plugins/system/sellaciousreportscart/sellaciousreportscart.php on line 27'
I wanted you to know that since you haven't provided us any details for the cPanel or FTP, I just logged in to Joomla administrator of your site and tried to update the sellacious. Let me know if the sellacious installation is working for you after retrieving.