Adapter

More info please. What type of devices?

If all you are asking about is the plug adaptor, the standard British one works fine. You can get one right here from the RS Store for $1 that works fine as long as you are not talking about a high current device. Most cell phones, tablets, camera chargers, all will work fine with just the plug adaptor. Check to make sure they can handle 220V 50Hz power. Forget things like hair dryers and curling irons and electric shavers. If you need those, buy a cheep one once you arrive.

Plugs in the UK come with sleeved pins - the one RS sells wouldn't be allowed to be sold in the UK. I wonder how safe it is?

This is what sleeved pins look like

https://www.johnlewis.com/john-lewis-uk-plug-3-amp/p231577941

Thanks

Teani

See Rick Steves FAQ tip: https://www.ricksteves.com/travel-tips/phones-tech/electric-adapters-converters
Modern electronics operates on low voltage DC current and typically comes with a step down voltage converter. And most "automatically" detect voltage input and do the right thing. If your adapter is rated for 110-240 vac 50-60 Hz your are good with a plug adapter to patch the UK outlets.

You may be able to buy the sleeved ones locally. I found them at my AAA store, so take a look at their travel store if you have one nearby. They had both the unsleeved and the sleeved ones. You can also probably find them at either your departure or transit airports.