It has been mentioned in a previous post, electric towel rails as are wet system ones, are not over productive in generating heat, they a devised to keep towels warm not heat rooms.
For heating room efficiently you would require to measure room and u values of fabrics/materials and temperature differentials between rooms and the external environment plus air changes. So you can then calculate the heat loss requirements of that room, therefore size the correct heating panel.
For heating room efficiently you would require to measure room and u values of fabrics/materials and temperature differentials between rooms and the external environment plus air changes. So you can then calculate the heat loss requirements of that room, therefore size the correct heating panel.