Very many of you on the beach? (9)
I believe the answer is:
thousands
'very many' is the definition.
'thousands' can be an answer for 'many' (thesaurus). I am not certain of the 'very' bit.
'you on the beach?' is the wordplay.
'you' becomes 'thou' (historical second person pronoun).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'the beach?' becomes 'sands' (sands can mean a beach area).
'thou'+'sands'='THOUSANDS'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for thousands that I've seen before include "a lot" , "Crowds" , "Dan shouts out at many hundreds" , "large sum?" , "1000s" .)