Number wrong to be upset following board game (5,6)
I believe the answer is:
table tennis
'game' is the definition.
(I know that table tennis is a type of table game)
'number wrong to be upset following board' is the wordplay.
'number wrong' becomes 'sinnet' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to be upset' shows that the letters should be reversed in order (I've seen 'being upset' mean this).
'following' is a charade indicator (letters next to each other).
'board' becomes 'table' (both can mean food).
'sinnet' backwards is 'tennis'.
'tennis' put after 'table' is 'TABLE-TENNIS'.
Can you help me to learn more?
(Other definitions for table tennis that I've seen before include "sport" , "Ping-pong" , "Ping pong" , "Indoor game" .)