Househunter,
We have recently redone our bathroom. Although we have a radiator in the bathroom, we decided to put in some electric underfloor heating.
A builder friend of mine gave me some electirc u/f heating matting and I sourced a control panel/thermostat from an online UK heating supplier. Electrician had no problem connecting it all up. Result is toasty feet.
One thing to make note of is that you must cover as much of the floor as possible with the matting. We tiled ours with porcelain tiles and a few small areas that I did not cover with matting do not heat up at all. I thought that some heat would have transferred to these areas through the tiles, but that doesn't seem to happen.
teddyk.