Couldn't find out how to delete this but please ignore - found the problem - I had settings for updates via FTP, once I changed those it worked fine .
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Given I didn't have this problem prior to RSFirewall, I'm presuming it's due to some setting or other within it that I now suddenly can't install Joomla updates automatically through Joomla by using components e.g. Joomla Updater etc.

I've got the Firewall backend access to accept me as User plus have all the components highlighted incl the com_installer & com_template (which is where the error seems to point) and also have gone into the Active Scanner and told it to ignore those for SQL injections. I'm unsure what other variables I need to switch off to allow for such updates.

I appreciate that this is always going to be an issue with a security feature - how to ensure that it allows those things that are necessary but could be carrying something else along the way, over those you just plain don't want to allow under any circumstances and covering all bases at the same time, so I'm content this is most likely down to my inexperience with the RSFirewall component, but perhaps someone could advise me on how best to fix this problem?