You’re linking to your collection “east-cost” and also products tagged “East Coast” - that’s why you’re seeing it show up twice. You can’t get rid of the lowercase east-coast in the URL because that’s how shopify handle’s work, also having uppercase letters in a url is just unusual in general.
https://www.silverstork.co.uk/collections/east-coast
What’s the problem with your images though? They look fine to me. If you think their grid is taking up too much space, I assume there’s a setting in your Customize editor on your collections pages to show more products per row, that would make your product cards smaller. Right now they are taking up 25% of the screen space so it’s likely set to 4 per row.