Gahl1k :
They are higher for a reason — shipping cost from the U.S. to U.K. will tear your money apart.
They're higher because the UK has VAT. A component is taxed at every step in the manufacturing/resale process. In the U.S. it's only taxed at final sale. VATs are useful for streamlining the manufacturing process (encourages buying direct from manufacturer instead of via middlemen) and discouraging speculators, but it results in higher end-user prices.
If you buy the component in the U.S. and have it shipped to the UK, legally you'd have to declare what it is you're importing on the customs form, and pay import taxes and duties which would include a VAT-equivalent, making the price the same if not higher (shipping). If you know someone visiting the U.S., they can buy it for you and bring it back to the UK within their duty-free allowance (up to £390).
https://www.gov.uk/duty-free-goods/arrivals-from-outside-the-eu
Sometimes stores will do the traveler importing for you (even though they're not supposed to - the duty free allowance is for personal use, not for items to be resold). These items are sold as "grey market" and usually lack a warranty and/or have limited return options.
On the flip side, if you're from the U.S. visiting the UK, you can get a VAT refund at the airport if you show you're taking the products outside of the UK. It's a short form you have to fill out, and you have to show the store receipt (to confirm you bought it in the UK) and the products (to show you're physically taking them with you out of the UK). Be careful though. The one time I tried this, I discovered they'd placed the customs booth
after baggage check-in. Since I no longer had my luggage, I couldn't show them I had the items, and couldn't get the VAT refund.