Front ride height

I’ve recently put some different springs in the front end of the car to lower it slightly (was meant to be about 20mm) but it has had little effect. I’m now talking to the supplier about this – they reckon my car had sagged and so it was already “lowered”. So, if anyone can be bothered, I’d like to know what the ride height is on a few different cars. The measurement I need is simple to do – just measure the distance from the wheel centre to the lip of the mudguard (preferably in millimetres). Thanks in advance.

Alex