If you removed all sidebars and your content is still centered, that is because you have your main content width set to something other than 100%. Go to the customizer under the Layout section and increase the width for your main content.
Thanks for the advice. I had actually checked this and it is set at 100% and is also showing the content centred in the preview pan on the dashboard but once I save and go to the site it is then aligned to the left and no longer centred. It is centred on mobile portait but not on landscape nor on desktop.
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Thanks for letting me know.
Y.