Hi Jordan,
Nick here from Shopify.
There are a couple of apps from the Shopify app store which spring to my mind within the UK. The first one is the Royal Mail app which you can see here and another is Zenstores which you can see here. Zenstores has a great rating and supports a lot of countries giving you a wide variety of who to choose from, but it would be a higher monthly cost to other shipping apps. The couriers within Zenstores are very UK based also.
These are the top UK apps which spring to my mind, I had a look in the App store and couldn't find any others which are as applicable to the UK as these. Hopefully, you can find what you need from one of them.
Can I ask what you are doing currently for your shipping? Is there something specific you are looking for other than cost reduction also?
All the best, Nick
