hi, i think intergas would be the boiler for you. it would allow you to set the maximum temperature for you CH and then set a different maximum temperature for you hot water cylinder.
the reason this duel temperature control is good is it lets you set a higher temp for your hot water which need to be 60 degrees and then have a much lower temp for your rads.
intergas can also take more clever controls like an outside sensor which would adjust the boiler flow temp as it gets colder outside.
so you would just have the rad temp right to get your house warm and keep it there with out wasting gas or having hot rads.
hope that helps