Supposed to have done some magic round European court (11)
I believe the answer is:
conjectured
'supposed' is the definition.
('conjecture' can be a synonym of 'suppose')
'done some magic round european court' is the wordplay.
'done some magic' becomes 'conjured' (I am not sure about this - if you are sure you should believe this answer much more).
'round' indicates putting letters inside.
'european' becomes 'e' (abbreviation e.g. EU).
'court' becomes 'ct'.
'e'+'ct'='ect'
'conjured' going around 'ect' is 'CONJECTURED'.
'to have' acts as a link.
Can you help me to learn more?
(Another definition for conjectured that I've seen is " Hazarded an opinion".)