The gas fire will smell for a good 10/15 minutes after not being used for a long time. At first this is disconcerting, but it is very normal.
Daft question, have you checked that the blown air vents are not blanked off on the back, as somebody at the factory may have forgotten to remove the blank.
I don't know anything about the varioheat, but I do have the optional electric element and it is good, but expensive as a retro fit.
Colin