Does that model have glow plugs. If so disconnect them one at a time and measure the resistance of them with your multi meter. If they are high resistance they will not be heating and this makes your vehicle hard to start.

When was injection system last serviced ? Older diesels in cold weather do take a few minutes to start properly in cold weather..
As Peter said ...

all so give the hand primer a few pumps just to make sure the has not run back to the tank at night

There is also a timer relay that can cause this. Had the same yrs back so fitted a push button switch to over ride the timer in cold weather; works fine just press for 15 seconds, cheaper than a timer.

I had the same problem a few years back on my 91 1hz 80 series cruiser,I started out changing out the glow plugs after I found a couple were faulty but it did'nt make a lot of difference ,it ended up being the glow plug relay,it had fallen down into the inner guard upside down and got a belly full of water on a few deep river crossings up the Kimberly,this shorted out the relay and buggered it
I found a second hand one in the wreckers and it fixed it. Shell
Hope this helps.

See ya in the bush

Gaz n Shell

Yes do as PeterD suggested and if the glow plugs check out then it is most likely the glow plug timer. I had a push button put in via Auto electrician this solved the hard starting. Dont glow it for anymore then 15 seconds as you can burn out your glow plugs.

My brother has an old cruiser he waits for the glow plugs spins it over for enough that it would normally start then stops and immediately hit the starter again and it starts every time
Don't know why it just does