Hi Iorbita - yes I have the pro version, and I've followed your instructions. I can now access the sitemap in my browser with .htaccess activated, which is brilliant.
I've been working with Joomla long enough that I should have been able wot work this out for myself!
I'm still unable to submit the sitemap in Google Search Console, but I will leave it a while and try again later. I see from other peoples posts that it can take a few attempts to get it to work.
Many thanks for your help today :-) I'll let you know once I have successfully submitted the sitemap.
Ian