when our blow heating is on (we have an Ace jubilee 2008), and when only electric is on it "appears" to blow cold, but in fact it is warm, but has to work hard to heat the entire van.(if vent in toilet is open, but door closed you can easily feel the heat in a very short space of time).but in an "open space" it is colder the further away from the fire that the vent is.
We normally boost it with gas for about 20 mins, then switch to elec, and it keeps us comfortable.
I personally think the gas is a far better job, and the elec is great for keeping a nice temp through-out the day/night, but not great for heating the van from cold on a bitter day.
For you info we were away in early march, with frost etc.