Interfering demo's led me to change (10)
I believe the answer is:
meddlesome
'interfering' is the definition.
('meddlesome' can be a synonym of 'interfering')
'demo's led me to change' is the wordplay.
'to change' is an anagram indicator.
'demos'+'led'+'me'='demosledme'
'demosledme' anagrammed gives 'MEDDLESOME'.
(Other definitions for meddlesome that I've seen before include "nosy?" , "Interfering" .)