firstly, dont spray easy start, that stuff is like heroin for vehicles, you use that come winter you will be using it all the time.
right mate hopefully this will help a little, theres plenty of life left in a van of that mileage to say other ways is not right, you will by another van with new and different problems.
if the van isnt starting, it isnt getting air fuel or power
rule out the fuel by jump starting it from your dads car, if the battery is really knackered it may nit jump from the car, so if this happens take the battery off charge it and then go to start again.
even though it was trying to start, the battery may not have had enough power in it to start the vehicle (even though it sounds like it did)
if your trying to start it now and the battery seems to have charged fine and it is not starting still but the battery sounds fine and not instantly flattening whilst trying to start its something else.
forget glow plugs and starter motor, you would hear the motor and glow plugs shouldnt be a problem in this weather.
if its turning over fine but not starting look for anything on the dash that has a padlock or lock related symbol on it, this light should go out when you turn the ignition, if it is not going out you imobiliser is not going off, if this is the case its a dealership fix about £500 they normally replace ecu
if you get it started something has drained the battery beyond the ability to start the car, its possible that you have just left something on (cd player etc) however you should check the battery voltage with a multimeter and then again with the car running, make sure the voltage goes up after starting the car to see the battery is taking charge, halfords and garages will check the battery is taking charge for free.
if the battery isnt charging properly or holding charge you will know you need a new battery, halfords will also tell you the health of the battery
if the battery seems to be ok but is not charging when the van is running, you need to look at the alternator, first check the belt is in good repair, then check the cable (larger one) is connected properly to the body of the altinator and not snapped off, take of the terminal (after disconeccting the battery) clean it up and test again with the van running.
if the battery is still not charging you need an alternator. alternators will be about 150 for the part and should take under and hour to fit..
i hope this is helpfull to you mate