Adapters...

We ordered them from RS online. Cheap. Order extras, as you might accidentally leave some along the way.

Read this to better decide exactly what it is you need - an adapter or a converter - for your equipment:
https://www.ricksteves.com/travel-tips/phones-tech/electric-adapters-converters

Most modern devices will work on both 110 or 220, although some require manual selection of one versus the other to ensure compatibility.

A personal experience: After inadvertently frying a couple of her US hair dryers while traveling overseas, my wife finally just broke down and bought a cheap travel hair dryer that works on 220V. Haven't had any issues (or heartache) since.

RE: Most modern devices will work on both 110 or 220....

Automatic multiple voltage devices generally only apply to "electronics" devices that need to step down alternating current voltage commonly to about 5 volts dc.

Thermal devices such as irons would need to be designed specifically for dual voltage operation. Doubling the voltage to thermal devices doubles the power (watts) for the same current draw. You will know that your 120 volt iron is toast when you see a puff of smoke after plugging it into a 220 volt supply.

PS The UK plug is the Type G with two power electrodes in line and parallel with a a rectangular ground electrode perpendicular to the line of power electrodes.

I just came back from Ireland a week ago and had no problems using the following.

I had two RS UK plug adapters and used them with one of these 4-port USB adapters from Amazon. (http://www.amazon.com/Anker-Charger-PowerPort-Multi-Port-Foldable/dp/B00VH8G1SY?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00)

I charged my iPhone, my wife's Samsung Galaxy, our iPad's, my camera and even my FitBit with no problems at all.

Good luck and happy travels!
RF