Expression of surprise and cheers heard when introducing Seal (2,3)
I believe the answer is:
by gum
'expression of surprise and cheers heard when introducing' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'seal' is the wordplay.
I cannot really see how this works, but
'seal' could be 'gum' (I've seen this before) and 'gum' is found within the answer.
The remaining letters 'by' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for by gum that I've seen before include "Brother in N England" , "Mild oath (how things can be fixed!)" , "It's emphatically uttered" .)