In addition, the south side of a East-West oriented hugel bed, or better yet a south facing suntrap/keyhole hugel, will get up to 5C warmer than the flat ground,
My uncle in Bridgend had a laundromat and he wondered about collecting rain water to use in it.
When he called whatever government office to ask, the answer was : when it's in the sky it belongs to god, when it's on the ground it belongs to us, so no.
I agree with Ben. I live in western Washington State where the climate is also mild and maritime, and I value hugel beds for the things Ben mentioned as well. I have a LOT of water in my soil in fall, winter, and spring, and by putting hugel beds (which I garden in) in between the trees in my orchard I have been able to lower the water level there substantially.