Build up first-rate service (5)

I believe the answer is:

amass

'build up' is the definition.
(I've seen this before)

'first-rate service' is the wordplay.
'first-rate' becomes 'A'.
'service' becomes 'mass' (kind of church service).
'a'+'mass'='AMASS'

(Other definitions for amass that I've seen before include "Assemble" , "Gather in great quantity" , "Stock up on" , "Stockpile" , "store" .)

I've seen this clue in The Sun.

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