I want to add a box for customers to add personalisation text.

I’ve had it working in a previous theme with this code

  <label for="name-on-pottery">Name on Pottery (Max 12 characters)</label>
  <input id="name-on-pottery" type="text" name="properties[Name on pottery]" maxlength="12" style="width:auto !important;">

Now I’ve switched to Dawn theme, I tried making a new product template and added this as custom liquid file.

The box shows up on the product page but the personalisation isn’t showing on the cart page, so I don’t think it’s getting added. Any ideas why it worked on my old Minimal theme but not Dawn?