Got a second hand 2KW convector heater (minus installation instructions)
from a car boot sale. It's got wall brackets which unfortunately don't
line up with the wooden studs inside the plasterboard wall, so I've put
up a plank of 3/4" MDF and hung the heater on that. The brackets hold
the body of the heater about an inch from the MDF, and heating vents are
facing well away from it.

Obvious question approaching... Is MDF a good choice for this with
regard to the fire risk? I tried lighting a thin 2mm scrap with a match
and while it did char, it did not seem to be sustaining the flame.

I'm wondering if facing it with a piece of another material would be a
good idea. How about plasterboard?

How are electric heaters normally mounted in wooden buildings?

--
Adrian C