Can someone post instructions for getting air out the Hijet's radiator please?

Its bad news - the van is now un-driveable.

Today, I drove a mile from my house and noticed the temp needle was sat on the first bar of the 'H' (another few mins and I reckon the van would have blown - the needle was just past half way 'normal' when I left the house approx. 1.5 miles away)

I had an appt to go to, so when I came back to the van 40 mins later, it was cold and I could do the ritual water top up.  I then drove just 1/2 a mile to Sainsburys, and thank god I looked at the temp gauge again, and the needle was almost at the letter 'H' again!  I just managed to pull in off the dual carriageway and switch off)

I knew something was very wrong as the van has always gone back to normal temp for around 1 to 2 weeks after a water top up.  I got my shopping bits and made sure I wasted enough time for the van to cool, and this time, I took off the radiator cap as well as the under seat cap, so that as much air got out as poss, then I filled up the water to it's max and tried to get home.  This time was worse, and I didn't cover 1/4 of a mile before the needle went close to the max again.  I had to stop another two times to get home and top up over the course of less than one mile.
Yet again through all the water loss (bearing in mind there was no water coming out from under the van) the reservoir water container under the passenger seat never lowers or gets used.  
So, the van is dumped across the road, and I have no idea where to find someone who will know what to do with it.  I don't have the cash for the 'trial and error' way of fixing things in the hopes a cure will be found.

I honestly don't know what to do next  (My daughter said "Just sell it" but no-one will buy it in this state unless it goes for scrap value surely?)

Most hacked off
Tara

p.s
I'm going to start a new thread about the van, because getting air out of the system is obviously no longer an issue.