They say sitcom family cuppa has majestic quality (7)
I believe the answer is:
royalty
'majestic quality' is the definition.
(I've seen this before)
'they say sitcom family cuppa' is the wordplay.
I cannot really understand how this works, but
'family' could be 'royal' (royal family is a kind of family) and 'royal' is found within the answer.
'cuppa' could be 't' and 't' is located in the answer.
A single letter 'y' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'has' is the link.
Can you help me to learn more?
(Other definitions for royalty that I've seen before include "Palace residents" , "Sovereign rule" , "Sovereignty" , "payment for literary work?" , "Payment for the right to use someone else's property" .)