Updated PHP to latest version from 7.3 following WordPress health prompt. This resulted in welshbridgeunion.org displaying website from two days earlier on the machines of some users, whilst others viewed the website with the latest updates. This continued all through 24 hours and I reverted back to PHP 7.3. The problem still persists. DataCentre support say this appears to be a theme issue as it does not occur when using stock WordPress theme. We have had no previous problem with the premium theme.
the Theme has no control over what content is being served, this would be a server level issue. I notice when i right click > inspect your site there is an error relating to the WordPress Rest API function call that is used for Getting content. I would ask your hosts to look into the issue first to see if they can resolve that as it may be part of the problem.