Richard wrote:
3.5 x 3m conservatory what size electric heater will heat this room on
a winters night, it is one of those pentagon shaped conservatories.

Is convection or oil filled the best, I dont really want a fan heater.

couldn't you add a rad from the house CH ?

obviously more expensive (much cheaper if you DIY) and cost effective
in the long run.

sub £200 for a DIY number :-)