The afore mentioned GHOST123 here
The most common cause of your sudden "not turning over, just clicking" symptoms is a flat main battery.
I would either try the jump leads again, but follow this procedure = connect the black lead from the negative -ve of the car as usual but on the van end, connect it to a solid bit of metal work on the engine. The alternator bracket would be a good place. Connect the red positive jump lead up as usual (making sure it is on the main battery, not the leisure one

) Then, run the car engine for around 10 minutes before trying to start the van. Reasons = putting the black lead to metal on the engine helps eliminate any poor earths your van may have. And leaving it running for a while (the car) gives your van battery time to charge up.
Or
If that doesn't work, try bump starting it ! That should get it running. Then, when on the move and safe to try this, put it into neutral, turn the motor off and try to start it with the key. If it starts all well and good. If it doesn't, at least you are moving so you can dip the clutch, put it into gear (2nd usually, dependent on your coasting speed) and re-start it that way, to get you home.
Nice around Matlock isn't it

A better place to have to stay another night if the worst comes to the worst

Especially if there is a pub nearby.