Relative by river seeks Spanish noble (7)
I believe the answer is:
grandee
'spanish noble' is the definition.
(I've seen this before)
'relative by river' is the wordplay.
'relative' becomes 'gran' (I've seen this before).
'by' says to put letters next to each other.
'river' becomes 'Dee' (River Dee).
'gran'+'dee'='GRANDEE'
'seeks' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for grandee that I've seen before include "Angered over Spanish noble" , "Spanish bigwig" , "Person of eminence" , "aristocrat" , "European lord" .)