This cousin of the cowpea requires about 4 months to maturity. Usually used as a dried bean/pea. It has a myriad of names and spellings. Bush form about 2 feet tall, with yellow blossoms. Can be planted in the same manner as bush dry shelling beans.

Ditto on Farmerdilla's comments... except perhaps the DTM. Seed bought from the market would likely have a long DTM, but there are a few early varieties. I have one red-seeded variety ("Tarkara Early") that matures in 90 days. Another variety ("Buff", named for the color of its seeds) matures in just over 100 days. Adzuki beans bear heavily, for me about an ounce (28+ grams) per plant.

Not sure how adzuki would perform in the U.K. though. Like their cousins the cowpeas, they are heat lovers. You might have a better chance if you start them as transplants.