What do they call the word hardware in the UK

ironmongery

http://dictionary.reference.com/browse/ironmongery

In the United Kingdom, the term "hardware" is generally used to refer to computer hardware or general electronic devices. However, when it comes to home improvement or DIY (do-it-yourself) stores, they typically use the term "ironmongery" instead of "hardware." Ironmongery encompasses items such as hinges, screws, locks, and other hardware components used in construction or repair projects.

If you're specifically looking for computer or electronic hardware in the UK, it is still commonly referred to as "hardware." You can visit technology stores, electronics retailers, or online marketplaces that specialize in selling computer components or electronic devices.