i have removed the old bathroom rad and put isolation valves on. i'm
thinking of fitting a towel rad as it would be more useful, being able
to hang towels and dry them. the bathroom never gets cold anyway. is
running it from the plumbing the best idea, or running it from
electric? very often i think i would want just the towel radiator on
and no others, is this ineffecient as the water is running round the
whole system for just one rad to be on? is it better to just have it
electric then switch on / off as i please?

running it from the plumbing the best idea, or running it from
electric? very often i think i would want just the towel radiator on
and no others

I recently did my bathroom, and turned a normal towel rad into an
electric towel rad - you can buy straight elements (even B&Q do them)
and adaptor elbows, which allow you to use both systems - the water is
pumped as normal when the CH is on, but heated electrically when you
want it.

ISTR I paid slightly over the odds (about £27?), but was impressed
with the service nonetheless - and the adaptor elbows were a couple of
quid more - mine was from http://www.carltontech.co.uk