We have a trash compactor on our barge, a 12" wide under-worktop unit that compacts everything using an electrically operated ram. Absolutely excellent! It reduces well over a week's rubbish to a cube about 20" x 10" x 18" They are an American thing, about 700 dollars there. Not sure if they can be bought in England. We have one in the house as well!
They are actually very basic engineering and could easily be home built, perhaps built into a well deck locker. Basically a rectangular compartment that holds the rubbish, which is compressed by a steel plate on a scissor jack, chain driven by an electric motor. Could also be done hydraulically