Bank on the Spanish for bad verse (8)
I believe the answer is:
doggerel
'bad verse' is the definition.
(bad-quality poetry)
'bank on the spanish' is the wordplay.
'bank' becomes 'dogger' (Dogger Bank is a sandbank).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'the spanish' becomes 'el' ('the' in Spanish).
'dogger'+'el'='DOGGEREL'
'for' is the link.
(Other definitions for doggerel that I've seen before include "Unpretentious verses" , "Poor quality comic or trivial verse" , "Trite verse" , "Rubbishy verse" , "Irregular comic verse" .)