Jason you are a diamond, found out the caravan weighs 750kg so that's great as for the 50kg on the tow hitch I'm assuming a couple of bottles would sort that out.
Once again thanks for your help 8)
Yeah, basically make sure you are loaded so you can pick the front of the caravan up without too much effort. You'll knw if you have it wrong when the steering is a little light and the front wheels lock up under braking!!!