Soundsl ike a flat battery, you need serious jump leads for the TDi, been there done that.
On the backof the fuel pump you should see a wire, black. It goes to the fuel pump shut off solenoid, all you need to do is check that it's got 12v going to it, a bulb might suffice or a multimeter if you have one, check it stays at 12 volts whilst you are cranking.
You could also check the glow plugs are getting 12 volts whilst the glow plug light is on on the dash panel. these are 12 volts so you could try jumping them from the battery as a last resort. It's also possible they have all bust, I've found this in the past.