My car was built in 2005 and also has the blue springs (but not as clean as yours). I’ve always suspected my front end was a bit on the hard side. You can barely move it by pushing down at the front. A couple of months back Peter B got underneath with his tape measure and concluded my lowers had about 20mm of compression
I think he said it was comparable to the stiffness of an F1 car! So I’m eagerly awaiting my kingpins to developed slack so I get in there and play.
Not being able to manually move the front much is totally normal, try any other car and you will see the same. As for measuring the lower rebound spring....little exercise for you, if you have a front bumper grab the stays and do your best impression of a weight lifter and try and raise the car, or use a jack in the middle. Let it go and measure the lower springs.....now push the front down and repeat and you will find there is a considerable difference. The cars 'stick' either high or low by at least 20mm depending on how it was parked, did you roll to a stop, did you dab the brakes, did you power into the parking place more? Its all down to the 'stiction' in the kingpins and bushes and if you saw a car with kingpins and no stub axles and wheels assembled you would see the angle the pins sit at (corrected in geometry by the stub axle face not being parallel to the bush tube)....all a normal part of the geometry. Don't let a characteristic of the car sway you into thinking the rebounds are under load, an excellent video posted on here (somewhere) of a car driving down the road showed the rebounds have a massive gap above them most of the time anyway making a bit of a nonsense of this worry about preloading the rebounds. Of course you want smooth interaction between the kingpins and bushes but if it ain't broke why fix it?
