Unavailing product of Merseyside port's Society (8)
I believe the answer is:
bootless
'unavailing' is the definition.
(I've seen this in another clue)
'merseyside port's society' is the wordplay.
'merseyside port's' becomes 'bootle's'.
'society' becomes 's' (common abbreviation in names of organisations).
'bootles'+'s'='BOOTLESS'
'product of' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for bootless that I've seen before include "Be so lost (anag) - vain" , "Of little or no use" , "unprofitable" , "unlike puss in Perrault's tale" .)