Brake Fluid Mystery

This one has me baffled so hopefully someone can throw some light on it for me

Last year, Aug, a brake pipe looked iffy for MOT so decided to change them all and put braided flexibles on
Made all the bakes pipes myself and did the job in an afternoon

April this year while going round Dales doing a few B O A T 's noticed the brake light on dash came on when going down hill. Yes low on fluid, bought more, filled it up, came home.
Put it on ramps and got underneath, could not find any trace of fliud leaks at any joints or calipers. But 0.33l of fluid missing from resevoir must leave a damp patch some where
Have used none in last 3 weeks, even after another weekend in Dales.
Any one got any thoughts on where 1/3rd litre of brake fluid hides?

oh and to add to the mystery, no extra territory marks on drive, just the usual black oil from sump drips

Forgive me if Im wrong but doesnt the clutch slave share the brake reservoir on some disco's ?? if so Id be looking a slave cylinder of clutch master .

CHECK YOUR SERVO .iv,e found half a pint of brake fluid in there before now,,,,,dave

In reply to both

Thanks for the pointers, but no clutch and brakes totally separate systems, thanks for the pointers as I had to check, and may have een some thing I had missed


Servo - THANK YOU never thought of that one, and heard it form some one else as well now, so job for week end is loosen servo and dip finger into it see what transpires

Thanks for ideas, I have some thing to check