Eleven witches taste starter in cockroach, shame decapitated (8,4)
I believe the answer is:
coventry city
'eleven' is the definition.
(I've seen this before)
'witches taste starter in cockroach shame decapitated' is the wordplay.
'witches' becomes 'coven' (a coven is a group of witches).
'taste' becomes 'try' (try can mean to taste some food).
'starter in' says to take the initial letters.
'shame' becomes 'pity' (synonyms).
'decapitated' means to remove the first letter.
The initial letter of 'cockroach' is 'c'.
'pity' with its initial letter taken away is 'ity'.
'coven'+'try'+'c'+'ity'='COVENTRY CITY'
(Other definitions for coventry city that I've seen before include "Eleven" , "Sky Blues football team" .)