There aren't many Belfast agencies, or many in Northern Ireland at all, with genuine Magento 2 depth, because it's a platform that punishes dabbling. Upgrades are involved, extensions conflict, and performance needs constant attention. We've lived with it long enough to know its moods, and to know when a business genuinely needs it.
That last part matters. Magento earns its keep on complex catalogues, B2B account pricing and multi-store operations. If your store doesn't need that muscle, we'll steer you to Shopify or WooCommerce and save you money. If it does, you'll want a team that stays for the support years, because that's where Magento is won or lost.