I have an early Discovery 1 .
On trying to bleed the system due to gears getting difficult to engage and pedal a bit soft ,I'm finding there is no fluid being expelled through the bleed nipple when loosened and pedal depressed.
I'm keeping the fluid level topped up as the level drops when the pedal is released again.
As there is no leak visible on clean ground below vehicle, what is a likely cause ? A defective seal somewhere ? Where is the fluid going ?

I changed the hydraulic damper successfully about 500 miles ago which cured the problem and bled normally but now have this issue