My Apple 20W UK charger measures 49 × 45 × 30 mm, making it much smaller than this Ugreen one (50 x 50 x 42 mm).

I'm guessing an Apple 40-60W UK version might come in somewhere in between in size?

There's also the Anker Nano 45W, at 49 × 49 × 34 mm: https://www.amazon.co.uk/dp/B0DPR2VYQF