Perhaps survey and search island on new river in Yorkshire (13)
I believe the answer is:
questionnaire
'perhaps survey' is the definition.
'questionnaire' can be an answer for 'survey' (I've seen this before). I'm not sure about the 'perhaps' bit.
'search island on new river in yorkshire' is the wordplay.
'search island on' becomes 'question' (I can't explain this - if you can you should believe this answer much more).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'river in yorkshire' becomes 'aire' (I've seen this in another clue).
'question'+'n'+'aire'='QUESTIONNAIRE'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for questionnaire that I've seen before include "Survey fill-in form" , "List of enquiries" , "Form for market research" , "Survey answer sheet" , "List of inquiries" .)