It is important to note that when purchasing a new or replacement open vent regular gas boiler, unless it is installed with an additional hot water storage cylinder, then the boiler will only be able to provide central heating. You will also need to accommodate for an additional cold water tank and feed which are typically installed in the attic of a home.
The Vokera Mynute VHE range includes two boilers of different outputs of between 15kW and 20kW. This particular model is the least powerful of its range, with an output of 15kW, however, it is powerful enough to heat a home with up to 10 radiators and a bathroom. If you feel that your property has a higher demand for central heating, then the Easi-Heat Plus 18V and Mynute 20VHE Open Vent could be better suited to you.