Hi, @awaddon !
Thanks for reaching out to us about this.
While you may see that the payment gateway Realex Payments is supported on Shopify, it all depends on the country from which you are doing business. Not all payment gateways are available to every country.
I would suggest locating your country of business from this list to see if Realex Payments is available in your region. If it is not listed as a supported payment provider, you will need to select another option from that list.
I hope this helps.
Thanks for getting back to us, @awaddon !
I can see that Realex is available in the UK. Can you first confirm that your address under Settings > General is one located in the UK?
If so, you would need to add the payment gateway under Settings > Payments > Third-party providers here (not alternative payment methods):
If you are still not seeing Realex, please take a screenshot of the menu that's missing the option and post it here. Please be sure to include your store URL as well so I may take a deeper look.
I look forward to your reply.