Doctor must keep our strange band (5)
I believe the answer is:
group
'band' is the definition.
(I know that band can be written as group)
'doctor must keep our strange' is the wordplay.
'doctor' becomes 'GP' (general practitioner).
'must keep' is an insertion indicator.
'strange' indicates anagramming the letters.
'our' anagrammed gives 'rou'.
'gp' going around 'rou' is 'GROUP'.
(Other definitions for group that I've seen before include "Be exceptionally good" , "Take That, perhaps" , "Set; band" , "Number of associated individuals" , "Assemble" .)