Hello, Your guidance please. I have just checked the nose weight of my 2003 Puck 120 and its showing 50kgs. My Puck has a max laden weight of 650 kgs and my towbar takes max 78kgs. Is 50kgs good/too low/too high? I understand an ideal weight should be between 5 to 7% of the total weight, and 50kgs equates to 7.5% of the total weight (650kgs). The plate on the side of the caravan shows 1: 650kgs and 2: 75 kgs. Thanks for your help.

You don’t mention your tow car but most mid size cars would not even notice a Puck behind and the rear suspension should look more or less untroubled with the caravan attached. If the van is too heavy on the rear the car will feel unsettled over road bumps.

The 75kg on the VIN plate will be the maximum weight that the hitch is rated for. You also need to know the max of your car's towbar and the max. noseweight the car itself is rated for and the lowest of those three is the most your noseweight should be.
In addition be aware that an empty noseweight is no indication of the actual noseweight when the van is fully loaded. The 5 to 7% recommendation is 5 to 7% of the van's actual weight, which will not necessarily be it's MTPLM.
Remember that weight put over the axle has little or no effect on noseweight and the further it's moved away from the axle, the greater the effect. So a 10kg item placed on the hitch will add 10kg to noseweight, but place that 10kg inside the van, right at the front and it'll only impact 5kg or thereabouts to the nose as it'll be about halfway back to the axle.

Thank you for your replies and explanations.