What did you ask for, a nice looking realistic fire, or a functional
heater? I don't think the two things exist in one product. I also
have a proper gas wall heater of the same age, which is 2.9kW input
and 2.2kW output, which I used to use for real heating (it's now just
a backup if the central heating ever went wrong).
There are some with a convector section at the top that directs the
heat
into the room - a friend has one, don't know the model. Don't know how
flue gas / heat flow is separated etc., but it
gives out quite a lot of heat. Maybe the pebble stuff affects output.
You want the fake "coals" to radiate heat into the room also.
But of course you always lose some heat up the chimney.
Simon.