Apple's new 35W power adapter can charge two devices at once
Apple has introduced a new 35W compact power adapter, an accessory that has the potential to charge two devices simultaneously.

35W Dual USB-C Port Compact Power Adapter
Announced as part of the WWDC launch of the updated MacBook Air, the new 35W Dual USB-C Port Compact Power Adapter is the usual square wall-wart familiar to most users. At 35W, the charger can provide a lot of charge to devices, but it has a better party trick.
At the top are two USB-C ports rather than the standard single port. The change means that it is possible for one charger to be used to recharge two devices at the same time, splitting the wattage depending on what is connected.
The charger is advantageous, since it now means users don't need to keep as many of them on hand to recharge multiple items. This is handy for travel, as well as those who simply don't have enough power outlets in the home.
As is standard for Apple's small charger design, there are fold-out prongs and divots on the sides for grip. It is also compatible with Apple's World Travel Adapter Kit.
The 35W Dual USB-C Port Compact Power Adapter will cost $59. Aside from the United States, it will also be available to customers in Canada, China, Japan, Mexico, Philippines, Taiwan, and Thailand.
Read on AppleInsider

35W Dual USB-C Port Compact Power Adapter
Announced as part of the WWDC launch of the updated MacBook Air, the new 35W Dual USB-C Port Compact Power Adapter is the usual square wall-wart familiar to most users. At 35W, the charger can provide a lot of charge to devices, but it has a better party trick.
At the top are two USB-C ports rather than the standard single port. The change means that it is possible for one charger to be used to recharge two devices at the same time, splitting the wattage depending on what is connected.
The charger is advantageous, since it now means users don't need to keep as many of them on hand to recharge multiple items. This is handy for travel, as well as those who simply don't have enough power outlets in the home.
As is standard for Apple's small charger design, there are fold-out prongs and divots on the sides for grip. It is also compatible with Apple's World Travel Adapter Kit.
The 35W Dual USB-C Port Compact Power Adapter will cost $59. Aside from the United States, it will also be available to customers in Canada, China, Japan, Mexico, Philippines, Taiwan, and Thailand.
Read on AppleInsider
Comments
Folding pins on UK chargers aren't really a thing generally.
https://www.apple.com/us/search/35w
Like what you said, Apple could have copy the Apple Watch version, where the UK plug folds into the unit. But that might also be too bulky to be call "compact" as the folding UK plug takes up more internal space when folded in. Here's a tear down of it and it's only 5W. Very ingenious design. Not sure if Apple was first to come up with it.
https://www.ifixit.com/Teardown/Apple+5W+USB+Power+Adapter+(Folding+Pins+-+UK+plug)+Teardown/41045
Just look around on Amazon. A dual USB-C 65W charger can be had for $20. Heck I bought a few dual port USB-C 90W chargers for $18 (reputable brand).