The German editor went to Northern Ireland, having not understood, initially, overturned them and wasn't blocked (10)
I believe the answer is:
unhindered
'the german editor went to northern ireland having not understood initially overturned them' is the definition.
I can't tell whether this defines the answer.
'wasn't blocked' is the wordplay.
'wasn't' becomes 'un' (I can't justify this - if you can you should believe this answer much more).
'blocked' becomes 'hindered' ('hinder' can be a synonym of 'block').
'un'+'hindered'='UNHINDERED'
'and' is the link.
Can you help me to learn more?
(Another definition for unhindered that I've seen is " not held up".)