Discount codes don't appear to be working on my cart page, if the page POSTs to /cart with a discount parameter, it doesn't seem to be applied, no error messages or anything. If I post it to the /checkout page, it shows on the Shopify checkout page. It also works by inputting it on the checkout page. I can't see anything in my theme that would be causing this issue, is there an issue on Shopify's side with this?
You can view this at https://www.laurasconfectionery.co.uk/ using the discount code MUM15
This is just how Shopify works. Discount codes can only be applied in checkout.