There are a number of things that Drupal and Ubercart does out of the box that are brilliant. However, there are a few things that you will probably need to get your site running well and capable of dealing with payments and running as an e-commerce store in the UK.
Install the VAT module (http://drupal.org/project/uc_vat). As it is a requirement for most products sold in the UK to be eligible for VAT then you need a good way of dealing with it. The VAT module is perfect for that.
For shipping my preferred handler is the Table Quote module as it is fairly simple for most businesses to work out their shipping on a rate (if you spend £50 shipping is £10, if you spend £100 shipping is £18 etc).
This is on small change that I have been asked about quite a few times. There is a good tutorial here (http://technology.blue-bag.com/drupal-ubercart-changing-your-cart-your-basket).
Basically it goes through installing the String Overrides (http://drupal.org/project/stringoverrides) module and using that to replace the text in you site with other text. This would mean that you could change it to anything though, maybe think instead of “basket” what about “plant pot” or “backpack”? Have some fun!