Turn left twice on motorway to reach part of Scotland (4)
I believe the answer is:
mull
'part of scotland' is the definition.
(I know this)
'turn left twice on motorway' is the wordplay.
'turn' becomes 'U' (a 'U-turn' is a kind of turn).
'left twice' becomes 'll' (I can't justify this - if you can you should believe this answer much more).
'on' is a charade indicator (letters next to each other).
'motorway' becomes 'M' (as in motorway names - Ml, M4 etc).
'u'+'ll'='ull'
'ull' after 'm' is 'MULL'.
'to reach' acts as a link.
Can you help me to learn more?
(Other definitions for mull that I've seen before include "Point for Scots" , "Heat wine with sugar and spice" , "Consider" , "Island of the Inner Hebrides -- think long and deeply" , "Inner Hebridean island" .)