I just finished reading "With the Jocks" by Lt (later Capt) Peter White. It's a very honest and graphic story of the British advance during WWII, written directly from his diary entries while serving as a platoon commander with 4 KOSB.
Among other things, White writes candidly about he and his troops taking advantage of the local hospitality during thier advance through Belgium, the Netherlands and eventually Germany. He mentions how he and the troops would be willingly boarded and fed in Belgium and Holland, though given these civilians had next to nothing themselves, they were very careful to stick to their own rations/supplies. Germany, on the other hand, was a very different story.
White notes that both he and the troops would routinely enter a German village and give the residents a brief period to clear out of rooms or an area so they could rest, eat, set up HQ, etc. They would often occupy part of a farm or house with the occupants, encouraging the inhabitants to cook and share what they had. He mentions that his troops would frequently scrounge for food and slaughter livestock whenever the need arose. Wine cellars were a common target as well. He recollects that several of his chaps liberated various items from both enemy troops and civilians (waatches, jewellry, etc) and while he didn't encourage it, I recall he acquired a few souvenirs for himself too.
While perhaps not permitted in offical UK policy, White's story makes it clear that nearly anything and everything occurred, especially during the frenzy of April and May 1945.