Does this mean that you can use a hot-water supply for a dish-washer ?

No get a Y-piece for the cold connection to connect both washing machine and
dishwasher to that. If you must, check your dishwasher instructions. Mine
says I can use a hot feed limited to 55C maximum temperature (difficult to
achieve with a traditional gravity fed cylinder). If this is done, it states
that it will reduce cycle time by 20 minutes but result in poorer wash
performance.

Christian.