Head of organisation, one on about tax, getting enthusiastic reception (7)
I believe the answer is:
ovation
'enthusiastic reception' is the definition.
(I've seen this before)
'head of organisation one on about tax' is the wordplay.
'head of' indicates taking the first letters.
'one' becomes 'I' (Roman numeral).
'about' says to put letters next to each other.
'tax' becomes 'vat' (UK Value Added Tax).
The first letter of 'organisation' is 'o'.
'i'+'on'='ion'
'ion' after 'vat' is 'vation'.
'o'+'vation'='OVATION'
'getting' acts as a link.
(Other definitions for ovation that I've seen before include "Applause, acclaim" , "Enthuiastic applause, often standing" , "enthusiastic response" , "Stormy applause" , "Prolonged applause" .)