Unearth former accountant’s tax notice at the bottom (8)
I believe the answer is:
excavate
'unearth' is the definition.
(I've seen this in another clue)
'former accountant's tax notice at the bottom' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'accountant' becomes 'CA' (abbreviation for chartered accountant).
'tax' becomes 'VAT' (British sales tax).
'at the bottom' suggests the final letters.
The final letter of 'notice' is 'e'.
'ex'+'ca'+'vat'+'e'='EXCAVATE'
(Other definitions for excavate that I've seen before include "Dig a hole" , "Recover through digging" , "mine" , "With spade" , "Quarry" .)