Recorded engineers and soldier joining desert manoeuvre (10)
I believe the answer is:
registered
'recorded' is the definition.
('register' can be a synonym of 'record')
'engineers and soldier joining desert manoeuvre' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'and' is a charade indicator (letters next to each other).
'soldier' becomes 'GI' (term for US soldier).
'joining' says to put letters next to each other.
'manoeuvre' indicates anagramming the letters.
'desert' anagrammed gives 'stered'.
're'+'gi'+'stered'='REGISTERED'
(Other definitions for registered that I've seen before include "As some nurses" , "indicated" , "Sunk in" , "Officially recorded" , "as post may be" .)