Discovery Ride Height

I have a Lreg 300 tdi and i hope that People on the forum could give me some advice on what the factory ride height should be from the wheel arch to centre of wheel
I am thinking of putting new springs and shocks on any advice would be good I want to keep the same ride height as it should be
I carry 3 Large german shepherds in it every day so the stiffer the springs the better
What is eveyones thoughts on the make and type of set up i should use
Thanks in advance

have a look ere.land rover spring specifications