You need to start with a heat store like shown
here These cylinders come in two types vented and un-vented the vented do not require annual testing as not a pressure vessel so I would think best option.
These cylinders allow you to have various hot coils and immersion heaters so you can combine the heat from many sources to heat the water. The water is often very hot so for the domestic supply a mixer valve is used to reduce the temperature of the hot water at the taps.
The water can be pumped around like with any other wet central heating system but unlike the storage radiator once the circulating pump is stopped there is nearly no loss of heat so you don't have to guess how warm the next day will be.
The disadvantage is weight and size of the storage tank. Plus installation cost. But it is the only way to combine solar, wind, and mains electric into one system.
The Ulster people have a really neat way of using a standard cylinder to do this job look
here Likely cheaper method as not using special cylinders. The problem is to stop the water mixing too much and you want to heat from top down rather than bottom up so hot water is available quickly. Other systems have baffles in the tank as seen here
but the solar syphon used by Willis seen here
is a far simpler idea to get same result. These Irish are claver people!
However finding a plumber in the main land who will install the system may be something else.