He says yes to a Spaniard and Scotsman (5)
I believe the answer is:
simon
'he says' is the definition.
(I've seen this in another clue)
'spaniard and scotsman' is the wordplay.
'spaniard' becomes 'si' (I can't justify this - if you can you should believe this answer much more).
'and' says to put letters next to each other.
'scotsman' becomes 'mon'.
'si'+'mon'='SIMON'
'yes to a' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for simon that I've seen before include "One of Christ's apostles" , "disciple" , "Harris and Coveney" , "Apostle Peter's other name" , "Bolivar, de Montfort, Callow or Cowell?" .)