If you take off the cover for where the servo is in front of the passenger seat you can see the action of the brake into the servo, hence if there is an issue with the linkage, however does not explain loss of fluid....
Peter
I went one better and bit the bullet.
I treated myself to a lunchtime quit which equates to a 4:30 AM start tomorrow but it's proved worthwhile.
After removing the master cylinder, I found my missing brake fluid lying in a pool inside the servo.
I sucked out around 100cc with a mi-t-vac and I'm going to steal the m/c off my other spider when I've finished my coffee.
I had rebuilt the obviously faulty cylinder about three or four years ago and I've never been really happy with the brakes since.
I did the front calipers at the same time and while there was a marked improvement, the result never matched my expectations or my rose coloured memory of my much lamented 1976 fiat 132 which even by today's standard, had great brakes.
Hopefully I'll see a marked improvement in performance when I'm done this evening.
I have a new rebuild kit but I'm reluctant to spend time doing the job in case I repeat whatever mistake I made originally.
Anyway, I'm pleased to have discovered the leak and I consider it time well spent