Got on with extremely top-notch diver at sea (7)
I believe the answer is:
arrived
'got' is the definition.
('arrive' can be a synonym of 'get')
'with extremely top-notch diver at sea' is the wordplay.
'with extremely top notch' becomes 'ar' (I can't explain this - if you can you should give a lot more credence to this answer).
'at sea' indicates an anagram.
'diver' with letters rearranged gives 'rived'.
'ar'+'rived'='ARRIVED'
'on' is the link.
Can you help me to learn more?
(Other definitions for arrived that I've seen before include "Reached a destination" , "completed the journey" , "Came" , "A driver (anag.)" .)