I am recently the proud owner of a 1978 fiat 500 Giardiniera.Being in the UK i was thinking that when the season changes and the weather gets damp, will i have a problem with steamy windows etc.I've seen two vents on the dash and pipes going to them.There is no heating as such is there?

At last, an easy one! There IS a very effective heater. There is a tiny lever on the centre tunnel in front of the back seat that you can reach while driving with your left hand. It simply turns left and tight with the sound increasing when in the open position. I suppose you could have it half way. The heat comes rushing down the tunnel to the front of the car where it splits at the tubes you have seen. The heat level varies only according to how hot the engine is...it's all or nothing!
There is a rotary flap on each steel tube above the driver's and passenger's legs. Whilst this increases the heat entering the cabin it equally reduces the amount continuing up two more corrugated tubes to the demisters. Effectively, heater on results in demisters on.
Let's hope that's the worst of your problems. Good luck.