If you dont want to move existing pipework, an Electric towel radiator is a great solution as it works works on mains electric and is independent of your central heating system. They come pre-filled with a specially treated water solution to protect against scale and corrosion and extend its life. They are installed on the wall as normal however an electrician is required to do the work rather than a plumber. There are various types of controls that can work with it, all of which will allow you to turn the heat on or off at the touch of a button or turn of a dial for your convenience. It also means that they are cheap to run as they only work when you need them to.