Cannot Imput Credit Card DEtails

I am a theme developer and a client hired me to build a completely bespoke theme for his needs.
I built a similar theme for another client and that works perfectly, However on this one after adding all the WooCommerce support in my functions.php file It seems no one can checkout or enter their credit card details to the website.
The are zero error logs on the site, the host and the theme. I have rolled back the plugin and testing it in php versions 7.3, 7.4, 8 and 8.1, the last 2 actually break the site so have left it on 7.4 for now.
I have a feeling it maybe a css issue but I cannot be entirely sure.
Any help would be greatly appreciated.

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