Hello Ashley,
The WooCommerce Gateway Stripe plugin is loading this iFrame:
<iframe name="__privateStripeFrame2619" frameborder="0" allowtransparency="true" scrolling="no" role="presentation" allow="payment *; publickey-credentials-get *" src="https://js.stripe.com/v3/elements-inner-payment-d7a16fc3dac481dbfae5ce9218e21a87.html#wait=true&rtl=false&publicOptions[fields][billingDetails][name]=never&publicOptions[fields][billingDetails][phone]=auto&publicOptions[fields][billingDetails][email]=never&publicOptions[fields][billingDetails][address][country]=never&publicOptions[fields][billingDetails][address][postalCode]=never&publicOptions[fields][billingDetails][address][state]=never&publicOptions[fields][billingDetails][address][city]=never&publicOptions[fields][billingDetails][address][line1]=never&publicOptions[fields][billingDetails][address][line2]=never&publicOptions[terms][card]=never&publicOptions[wallets][applePay]=never&publicOptions[wallets][googlePay]=never&locale=en-GB&elementsInitSource=stripe.elements&componentName=payment&keyMode=live&apiKey=pk_live_51NzFFEDHlEEmUokRZDEgM0A3erIbkMtbd0UzcYd1WqgrLBv4I5qqFdOdfyIpyVIEf4mfLsQ1gRlOjG0eFyMlAKM300YDoIlMVH&referrer=https%3A%2F%2Fwww.ocduk.org%2Fcheckout%2F&controllerId=__privateStripeController2616" title="Secure payment input frame" style="border: 0px !important; margin: -4px; padding: 0px !important; width: calc(100% + 8px); min-width: 100% !important; overflow: hidden !important; display: block !important; user-select: none !important; transform: translate(0px) !important; color-scheme: light only !important; height: 60.6484px; opacity: 1; transition: height 0.35s, opacity 0.4s 0.1s;"></iframe>
I would recommend that you create a staging site so we can troubleshoot thoroughly without affecting the live site.
Thank you.