A lot of sheep across Spain (5)
I believe the answer is:
reams
'a lot' is the definition.
(I've seen this in another clue)
'sheep across spain' is the wordplay.
'sheep' becomes 'rams' (male sheep).
'across' indicates putting letters inside.
'spain' becomes 'e' (abbreviation for Espana).
'rams' going around 'e' is 'REAMS'.
'of' is the link.
(Other definitions for reams that I've seen before include "Lots of paper" , "a very large amount" , "Scrapes the barrel" , "This much paperwork" , "Large quantities (of paper?)" .)