Thank you for posting here in the Community. I can share some insights into our QuickBooks Desktop products.
Currently, switching QuickBooks Desktop US version to the UK version is unavailable. Subscribing to another version requires to buy a new license number. You can install and run multiple versions and editions of QuickBooks on the same computer. You can open different versions at the same time, whereas different editions must be opened one at a time.
Let's download first the QBDT UK version on your computer. Here's how:
After that, you can now install the product. You have two options for installing QBDT either express or custom and network. And make sure that you already have the license number. Once verified, please check out this article for the detailed steps on how to install the product, depending on what install types, you want to use: Install QuickBooks Desktop.