I've noticed that Xbox One's sold in America tend do be around £100 cheaper in most cases, and due to this I was considering buying from a large brand like Walmart and having the console shipped over to the UK. My main reason for buying it is for games, so I'm not particularly fussed about things like TV not being perfect, but are there any major risks associated with it, or will it prevent me from playing games? (I tend to buy discs rather than download games)
However, it appears that some if not all downloaded games and content are. The good news is that the digital locking is based on your Xbox Live account, rather than where your console was sold. So if/when you sign up for an Xbox Live account, just make sure to enter the UK as your location.
Games are not region locked. Online content is locked to the account. So if you buy an Xbox from the states, and log in to a UK account with it, you have no problem with any content you have already purchased and can access the UK store, no worries.
As for the power, American walls regulate to about 110 with UK regulating to 240. You should check the price of an inverter (the device you need to handle the voltage change).
Keep in mind that cheaper inverters are designed for 10 minute use (hair dryers, toasters etc.) Where an Xbox will require a more expensive unit to handle the constant use.
Here in Australia electronics are more expensive (I buy my games from the UK to save money) but the inverter would be about $100 from the last stock I seen.