The available options.
Given that you have a central heating system circulating warm water around the house, a radiator in the bathroom is probably the most popular choice for heating, but which one, as there is a vast range of choices available?
Panel or convector radiator.
This is the standard type of radiator which you will see throughout most houses, and will heat any bathroom well if the correct size is fitted. There is a wide enough range of sizes and shapes readily available to allow you to find something suitable. The convector style will be a double panel with a vent fitted on top. This design allows warm air to rise upwards from between the panels and thus should not be blocked by anything sitting on top. So no towels or shelves should be placed above, or anything which might block the rising warm air.