Rads are too hot even though room stat set at 20c?

The house rads are almost too hot to touch even though room stat set at 20 deg. Turned boiler down to 2 (out of 5) which has helped but hot water now not really hot enough (hot water tank stat set at 60 deg). The boiler is an ideal classic ff 360 and is about 7 years old. Is it the room stat or something on the boiler itself? thanks