Lad is drunk after Savoy's first quit for another label (the mug!) (4)
I believe the answer is:
dial
'the mug' is the definition.
(I've seen this in other clues)
'lad is drunk after savoy's first quit for another label' is the wordplay.
I cannot really understand how this works, but
'first' could be 'i' (I in Roman numerals eg Elizabeth I) and 'i' is found in the answer.
an anagram of 'lad' is 'dal' which is present in the remaining letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for dial that I've seen before include "Clock face" , "Meter face" , "Calibrated face" , "Face of a timepiece" , "Watch face" .)