One asking questions in Bury, right old reptile! (12)
I believe the answer is:
interrogator
'one asking questions' is the definition.
(someone interrogating people)
'bury right old reptile' is the wordplay.
'bury' becomes 'inter' (synonyms).
'right' becomes 'r' (common abbreviation).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'reptile' becomes 'gator' (short for alligator).
'inter'+'r'+'o'+'gator'='INTERROGATOR'
'in' acts as a link.
(Other definitions for interrogator that I've seen before include "Inquisitor" , "one grills" , "Cross-examiner" , "Questioner" .)