Old man given £1000 twice a year (9)
I believe the answer is:
grandpapa
'old man' is the definition.
(term for grandfather)
'ps1000 twice a year' is the wordplay.
'psg000' becomes 'grand' (I can't explain this - if you can you should believe this answer much more).
'twice' says to double the letters.
'a year' becomes 'pa' (per annum).
'pa' doubled is 'papa'.
'grand'+'papa'='GRANDPAPA'
'given' is the link.
(Other definitions for grandpapa that I've seen before include "Ancestor" , "senior relative" .)