Issues upsetting leaders of North of Ireland tourism divides Ulster, for one (8)
I believe the answer is:
editions
'issues' is the definition.
(edition is a kind of issue)
'upsetting leaders of north of ireland tourism divides ulster for one' is the wordplay.
'upsetting' shows that the letters should be reversed in order.
'leaders of' suggests taking the first letters.
'divides' indicates putting letters inside.
'ulster for one' becomes 'side' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The initial letters of 'north of ireland tourism' is 'noit'.
'noit' put inside 'side' is 'snoitide'.
'snoitide' reversed gives 'EDITIONS'.
Can you help me to learn more?
(Other definitions for editions that I've seen before include "Impressions given!" , "Repros" , "Particular forms of published texts" , "issues for the press" , "Numbers" .)