My S1 Roadster developed clutch creep which turned out to be fluid passing between the seals in the master cyl (no external leak) so you may have the start of that
To test, engine running, hold the clutch pedal depressed with it in gear, after a few minutes the car will start to creep forward & is difficult to pull back the gear lever into neutral, pump the clutch & all seams okay, but hold the pedal down & it will happen again
Hope this helps
Good lord...I had that on a Triumph Herald when I was 17. If I was waiting at a junction it would decide to pull out on it's own. Gave one of my Aunts a severe fright!
Nick