Is there a way to create something like:
3 days delivery (+5£)
Next day Delivery (+9£)
so the customer can choose on checkout? Is there a module to do this?
I've used the WebShopApps MatrixRate Shipping module on a couple websites and it works great. You can do exactly what you are wanting to do with this module. Create multiple shipping options like:
You can also set different shipping options and different prices based on the shipping location. You just upload a CSV file through your Magento admin.